DATA SHEET 29 - Camping and Caravanning Club · The computerised systems on modern cars make the...

A to wbar undergo ing typeapp ro val tes t ing at W it ter.

If you are con siderin g tow in g a foldin g cam per, trailer ten t or an y oth er trailer, all th eIf you are con siderin g tow in g a foldin g cam per, trailer ten t or an y oth er trailer, all th e

com m en ts apply to you r u n it too, bu t w e've u sed th e term 'caravan ' th rou gh ou t forcom m en ts apply to you r u n it too, bu t w e've u sed th e term 'caravan ' th rou gh ou t for

con ven ien ce an d con sisten cy. B en efit from free tow -m atch in g w h en you con ven ien ce an d con sisten cy. B en efit from free tow -m atch in g w h en you join th ejoin th e

C lu bC lu b ..

The tow ing o f t ra i le rs by ano the r veh icle p robab ly da te s ba ck to the invent ion o f the w hee l but

the invent ion o f the tow ba r and ba l l h it ch, o r tow ba l l, can be t ra ced to W es t fa l ia in 1932. The

idea w as granted a pa tent on 14 Ma rch 1934, and ha s s ince la id the founda t ions fo r many o f the

tow ing s ys tems w e know today.

In pos t w a r Europe a s ca r ow ne rsh ip grew so d id the demand

fo r tow ba rs . The re w as no regu la t ion and no th ing to s top

anyone from de s ign ing and f it t ing a tow ba r from a few p ie ce s

o f ang le iron.

It w as no t unt i l 1 Augus t 1998 (20 Apri l 1999 in No rthe rn

Ire land) tha t s a fe ty regu la t ions w e re int roduced to re ct i fy the

s itua t ion. The se s ta ted tha t a l l new ca rs re g is te red from tha t

da te m us t on ly be f it te d w ith type approved tow ba rs

produced in a cco rdance w ith European D ire ct ive EC 94/20.

The d ire ct ive requ ire s a s ample o f e a ch type o f tow ba r ha s to unde rgo a proce s s invo lve s a tw o

m il l ion cycle fa t igue te s t , w hich typ ica l ly la s ts 60 hours . The tow ba r is then independent ly

inspe cted by the veh icle ce rt i f ica t ion agency in the count ry o f manufa cture . O n succe s s fu l

inspe ct ion the tow ba r is is s ued w ith a un ique type approva l numbe r and can then be s o ld a s an

approved un it .

D ATA SH EET#2 9 To w bars and to w ing e lectrics#2 9 To w bars and to w ing e lectrics #29

The type app ro val p late o n aW es t falia to wbar. T he 'D ' value is

the lo ad us ed fo r tes t ing . Thevert ical lo ad o r 'S ' value is the

max imum no s eweigh t the to wbaris des igned fo r.

D eco d ing the weigh t figu res o n a V IN p late

O n 29 O ctobe r 2012 the D ire ct ive w as e xtended to include l ight commercia l veh icle s be low

3,500kg Gros s Veh icle W e ight and a l l mo to rhomes ba sed on commercia l veh icle cha s s is cabs ,

rega rd le s s o f the ir Gros s Veh icle W e ight .

The 94/20 D ire ct ive a ls o s t ipu la te s the tow ba r mus t a t ta ch to the veh icle us ing ded ica ted

mount ing po ints provided by the manufa cture r. A furthe r re qu irement is tha t the tow ba ll mus t be

in a s pe cif ie d pos it ion in re la t ion to those mount ing po ints and no t the he ight from the ground.

It is up to the veh icle make r to ensure the tow ba ll pos it ion ing mee ts the regu la to ry

requ irem ents .

The 94/20 D ire ct ive ha s s ince been rep la ced by ECE (U nite d

Na t ions Econom ic Comm is s ion fo r Europe ) Regula t ion 55.

Th is ha s a l l the requ irements o f EC 94/20 but impose s s ome

ext ra cond it ions , the mos t impo rtant be ing a te s t on the

se conda ry coup l ing . Th is is the a t ta chment po int fo r a

breakaw ay cab le on braked t ra i le rs . How eve r tow ba rs

confo rm ing to EC 94/20 a re s t i l l a pproved and su itab le fo r

s a le , f i tm ent and use .

EC Approva l doe s no t jus t app ly to tow ba rs , it a ls o app l ie s to

tow ing e le ct rics . The se a re requ ired to confo rm to EC

D ire ct ive 2009/19 (e le ct romagne t ic compa t ib i l i t y). P le a se no te - th is re la te s to rad io in te rfe rence

and no t to the ope ra t iona l compa t ib i l i t y w ith any g iven ca ravan.

Identify ing the tow ing capacityA ll mode rn veh icle s a re f it te d w ith a Veh icle Ident if ica t ion Numbe r (V IN ) o r cha s s is p la te . Th is

may be found unde r the bonne t o r pe rhaps low dow n on a doo r p i l la r. The top f igure is the

Maximum Autho ris ed Mas s (MAM) o f the veh icle , in o the r w o rds the maximum w e ight it le ga l ly be

loaded to . The f igure may a ls o be re fe rred to a s the Gros s Veh icle W e ight (GVW ).

The next f igure is the Gros s T ra in W e ight (GTW ). Th is is the s um o f the maximum pe rm is s ib le

w e ight o f the veh icle p lus t ra i le r and include s the load ca rrie d . Ano the r w ay to look a t it is tha t

the f igure is the s um o f the a ctua l a xle load ings on e a ch axle . The la s t tw o f igure s a re the

maximum load ings o f the front and re a r axle s .

The d iffe rence be tw een the GTW and the MAM is

the tow ing l im it o f the veh icle a t it s g ros s

veh icle w e ight . In the e xample the tow ing

capacity o f th is Suba ru is 3,754kg - 1,945kg =

1,800kg.

Acco rd ing to European regu la t ions , a ca r’s tow ing

l im it is the maximum w e ight a t w hich:

T he moto r veh ic le tow ing a t ra i le r mus t be ab le to s ta rt the veh ic le

c om bina t ion – laden to it s maximum mass – f ive t imes on an uph i l l g rad ient

o f a t le a s t 12 pe r c ent w ith in f ive m inute s .

The two to p weigh t figu res are the s ame s o th is veh icleis no t s u itab le fo r to w ing

W hen cons ide ring w ha t you may be ab le to tow the C lub w ould a lw ays s ugge s t you s t ick to the

85 pe r cent re commenda t ion w he reby the Maximum Te chn ica l ly Pe rm is s ib le Laden Mas s (MTPLM)

o f the ca ravan shou ld no t e xceed 85 pe r cent o f the ke rbw e ight o f the tow ing veh icle . Th is f igure

can be incre a sed to 100 pe r cent fo r those e xpe rie nced a t tow ing. The ke rbw e ight f igure doe s no t

appea r on the veh icle 's V IN p la te but s hou ld be g iven in the ca r's handbook. It may o r may no t

be the s am e a s the 'Mas s in s e rvice ' f igure now be ing show n on the DVLA fo rm V5. Th is depends

on w he the r the w e ight o f the drive r (75kg) ha s been included - s e e g lo s s a ry.

Lega l ly, the MAM o f your ca r p lus the MTPLM o f your ca ravan, mus t no t e xceed the GTW o f the

ca r.

C an the veh ic le tow ?It 's ve ry im po rtant to know tha t s ome veh icle s a re no t de s igned fo r tow ing and tha t tow ing w ith

one w ould be i l le ga l. In the C lub 's e xpe rie nce the se o ften include s po rts e d it ions w hich may be

low e red o r have a body kit , 'e co ' mode ls and more re cent ly hybrid and e le ct ric veh icle s . Some

mus t have the tow ba r prepa ra t ion ins ta l le d a t the fa cto ry and the C lub doe s no t be l ie ve th is can

be ins ta l le d to preow ned veh icle s . Example s o f s uch veh icle s include the Fo rd Ka , Jagua r F type ,

s ome Aud i TT , Aud i S3 and s ome Skoda . O n the se veh icle s the Maximum Tra in W e ight f igure w il l

be z e ros o r da she s . So be fo re purchase do che ck the a ctua l veh icle you intend to purchase can

tow w ha t you w ant it to , th is may mean w rit ing to the head o ff ice o f the pa rt icu la r company fo r

confirma t ion.

Some veh icle s m ay have an ident ica l f igure fo r the GTW and MAM, in th is ca s e i f the MAM is

reduced by unde r load ing the veh icle it may be pos s ib le to tow tha t d iffe rence up the GTW l im it .

Fo r th is to w o rk the use r needs to be fu l ly aw a re w ha t the ir veh icle and t ra i le r combina t ion

a ctua l ly w e ighs . Y ou can do th is by taking it to a pub l ic w e ighbridge .

Th is car's cras h beam will need to be remo vedbefo re a to wbar can be fit ted

Fit t ing a to wbar to a mo dern car isno t fo r the fain t-hearted . Th is is

an A ud i A 6 s alo o n

A flange type to wbar g ives yo u lo tso f o p t io ns

Ano the r impo rtant f igure to bea r in m ind is the nosew e ight l im it o f the tow ing veh icle . Th is is

the maxim um s ta t ic dow n fo rce tha t can be app l ie d to the tow ba ll on any f it te d tow ba r.

Nosew e ight is impo rtant fo r s tab le tow ing and the gene ra l ly a ccepted f igure is tha t the m in imum

nosew e ight o f a t ra i le r (o r ca ravan) s hou ld be in the range o f 5 pe r cent to 7 pe r cent o f it s

MTPLM. Fo r a ca ravan w ith an MTPLM o f 1,500kg th is w o rks out a t 75kg to 105kg.

D ealer fit versus tow bar specialistW hile it 's pe rfe ct ly pos s ib le and le ga l to f it a

tow ba r yours e lf, i t 's no t s ome th ing to be

unde rtaken l ight ly. Apa rt from ensuring the right

bo lt s go in the right ho le s to the co rre ct to rque

the re is the w ho le que s t ion o f tow ba r e le ct rics to

cons ide r, and you may have to remove the re a r

bumpe r, cra sh beam , boo t f loo r, re a r l ights and

so on.

Fo r the se re a sons w e w ould re commend ge t t ing the w o rk done pro fe s s iona l ly. I f the veh icle is

new it m ay make s ense to have the fa cto ry f it te d un it ins ta l le d o r a s k the s upp lying dea le r to f it

the tow ba r fo r you. Tha t w ay the re a re un l ike ly to be any w a rranty is s ue s i f s ome th ing la te r goe s

w rong. Ano the r po int to bea r in m ind he re is tha t s ome veh icle s may need s ome fa cto ry

prepa ra t ion and m ay requ ire add it iona l coo l ing equ ipment i f they a re to be used fo r tow ing. A

ma in dea le r is be s t p la ced to know th is in fo rma t ion.

No tw iths tand ing the above the re a re many e xce l le nt tow ba r

f it t ing com panie s , s ome o f w hom w il l come to you to do the

w ork. Indeed m a in dea le rs may cont ra ct out tow ba r f it t ing to

such com panie s . To he lp you choose one the Na t iona l T ra i le r

& Tow ing As socia t ion (NTTA) ma inta ins a da tabase o f

Q ua l ity Se cured Accred ite d (Q SA) tow ba r f it t ing companie s .

The se companie s a re monito red and

as se s sed annua l ly by the NTTA to ensure

compliance w ith indus t ry s tanda rds ,

w o rkshop be s t p ra ct ice , cus tome r s e rvice

and pro fe s s iona l w o rkmansh ip . The NTTA 's w ebs ite ha s a use fu l tow ba r quo te too l fa ci l i t y tha t

w il l pu l l up those Q SA ins ta l le rs nea re s t to a g iven pos tcode .

T ypes o f tow barTow ba rs come in tw o ma in type s - those w ith a f ixed tow ba ll

and those w ith a de ta chab le one . Bo th can come w ith sw an

ne ck o r f la nge type tow ba lls . I f you 're conce rned about the

look o f the re a r o f your ca r you may w ish to cons ide r a

tow ba r w ith a de ta chab le tow ba l l. It may e ven be pos s ib le to

spe cify a tow ba r w he re the tow ba ll can be re t ra cted out o f

s ight w hen no t in us e .

Fixed tow ba lls a re bo lte d to the tow ba r. In the U K the mos t

popula r is the f la nge type , w hich mounts us ing tw o (o r

s ome t im es four) bo lt s . The se can be use fu l i f you to w ant to

add items such a s a b ike ra ck, bumpe r s h ie ld o r b lade

s tab i l is e r b ra cke t .

S wan neck to wbars can lo o k qu iteneat

W es t falia's vert ical detachab leto wball and to wbar

W it ter's detachab le flange to wbar W it ter's ho riz o n tal detachab les ys tem

Th is retractab le to wbar fro mW es t falia is o perated by an electricmo to r

A heigh t ad jus tab le to wbar asm igh t be fit ted to s o me 4x 4s

PC T 's un ivers al w iring kit

Mos t de ta chab le tow ba l ls te nd to be o f the sw an ne ck va rie ty a lthough you can ge t de ta chab le

mount ing f la nge s fo r f la nge type tow ba lls . De ta chab le tow ba l ls employ a lo ckab le qu ick re le a se

mechanism tha t a l low s the tow ba ll to be e a s i ly de ta ched and re a t ta ched w ithout us ing any

too ls . The m ount ing is usua l ly ve rt ica l, ie push up to lo ck but , i f s pa ce is re s t ricte d , a ho riz onta l

s ys tem m ay be used. Ve rt ica l lo cking type s le ave l i t t le to be s een once the tow ba ll ha s been

re le a sed.

T ow bar e lectricsThe compute ris ed s ys tems on mode rn ca rs make the tow ba r's

e le ct rics e ve ry b it a s impo rtant a s the tow ba r it s e lf. It 's no t

jus t the ca ravan 's road l ights tha t have to be pow e red but ,

a ls o the fridge and le is ure ba t te ry too . The re a re tw o

principa l w ays o f add ing t ra i le r e le ct rics to mode rn ca rs . The

firs t is the bypas s kit , s ome t imes know n a s a 'un ive rs a l ' kit .

The se w il l f i t m os t ca rs .

Bypas s kit s w o rk by taking a low current from each o f the

ca r's re a r l ight circu it s and us ing it to sw itch re la ys

conne cted to the ca r's 12 vo lt s upp ly. The re la ys then sw itch

the ca ravan 's road l ights s o they ope ra te a t the s ame t ime

as those on the ca r.

The current draw n by the re la ys is no rma lly low enough no t

to a ffe ct the ca r's e le ct ron ics . The dow ns ide o f th is

a rrangement is tha t the ca r's compute rs have no idea tha t a

Ins u lat io n D is p lacement T erm inals- if they have to be us ed s elect thetype that are go o d quality, s ecu reand p ierce the cab le in at leas t twop laces s uch as the b lack o neabo ve.

A veh icle s pecific kit fro m W es t falia

t ra i le r is a t ta ched and canno t the re fo re ad jus t to compensa te .

I f the re is no ded ica ted conne cto r fo r tow ba r w iring w e w ould re commend tha t a l l conne ct ions a re

so lde red and then cove red w ith hea t s hrink s le e ving .

Ano the r is s ue o ften a s socia ted w ith bypas s kit s is poo r conta cts caused by us ing insu la t ion

p ie rcing conne cto rs know n a s Insu la t ion D is p la cement Te rm ina ls (IDTs ) to hook up to the

veh icle 's w iring s ys tem . The se a re qu ick and ea sy to f it but can be unre l ia b le in the longe r te rm

if poo r qua l ity one s a re used. The ins ta l le r s hou ld s e cure them to the loom to reduce any cab le

s t ra in and they shou ld on ly be used inte rna l ly. H igh ris k a re a s s uch a s the eng ine bay shou ld be

made w ith crimp te rm ina ls and e xte rna l conne ct ions s hou ld e ithe r be s o lde r o r crimp te rm ina ls

w ith hea t s hrink pro te ct ion.

How eve r a t le a s t one manufa cture r doe s no t a l low s o lde ring

on it s veh icle s but doe s re commend good qua l ity crimps and

IDTs .

In a l l circums tance s i f the Cont ro l A rea Ne tw ork (CAN ) is

conne cted in to it is s t rong ly re commend they a re no t

s o lde red. The se a re s igna l w ire s and they can be a ffe cted by

the hea t o f s o lde ring tha t a lte rs the re s is tance o f the cab le

and po tent ia l ly g ive fa ls e re ad ings ba ck to the veh icle

compute r. Spe cia l is t conne ct ions s hou ld be provided to a l low

the re conne ct ion.

The s e cond w ay o f

provid ing tow ba r e le ct rics is by means o f a veh icle -s pe cif ic

kit . The bene fit s o f the se a re tha t the tow ca r know s w hen a

t ra i le r is a t ta ched and the veh icle 's re sponse s a re mod if ie d

a cco rd ing ly. Many mode rn veh icle s have Dynam ic Stab i l i ty

program mes tha t re a ct to w ha teve r s itua t ion the veh icle is

ope ra t ing in , w he the r a t ra i le r is conne cted o r no t . The

se t t ings fo r ABS, veh icle and t ra i le r s tab i l i ty p rogrammes ,

ride he ight and t ransm is s ion, may a l l need to change .

Veh icle -s pe cif ic kit s p lug into the veh icle 's w iring ha rne s s to

provide s e ven o r 13 p in s ocke ts a s requ ired . O nce f it te d , the

ca r's ECU is p rogrammed to w o rk w ith the new equ ipment .

The re a re tw o s o rts o f veh icle s pe cif ic kit s - O rig ina l Equ ipment (O E) and a fte rma rke t . The f irs t is

de s igned by, o r in clo s e co l la bo ra t ion w ith, the veh icle manufa cture r and the ins ta l la t ion w il l be

cove red by the ca r's w a rranty. The dow ns ide is cos t and the fa ct tha t s ome kit s do no t confo rm

to the fu l l U K spe cif ica t ions . Fo r e xample it 's no t uncommon fo r p ins s uch a s those s upp lying the

fridge and cha rg ing circu it s to be le ft unw ired (s ee Know n Is sue s ). Even s ome O E kit s tha t a re

f it te d a fte r the veh icle product ion may no t a lte r o r ad jus t the management s ys tem fo r comple te

tow ing integra t ion a s ce rta in pa rts w e re no t included a t the fa cto ry bu i ld s o it ’s w o rth a s king

w ha t s ys tem s the ded ica ted kit w i l l e ffe ct on your veh icle .

A fte rma rke t kit s a re cheape r a lthough ava i la b i l i ty may be a prob lem fo r new mode ls o f ca r. I f

tow ing is o f p rim e im portance it 's w is e to che ck the ava i la b i l i ty o f a s u itab le w iring kit f irs t .

C o nnect io ns being made in to thecar's co mputer w iring

W es t falia's A u to co de s ervice to o l isbeing us ed to tell th is A ud i that ato wbar and veh icle s pecific electricshave been fit ted

Twin electric s o ckets

Indicator ligh t te ll-ta lesA ll veh icle s e qu ipped w ith tow ba rs a re requ ired to have s ome fo rm o f monito ring s ys tem fo r the

t ra i le r d ire ct ion ind ica to rs , to confirm they a re w o rking co rre ct ly.

The s ys tem may be vis ua l o r aud ito ry o r bo th. The re ha s to be a ma rked change in the e vent o f a

bu lb fa i lure . W ith an aud ito ry s ys tem th is may be a d iffe rent fre quency o r no s ound a t a l l . A

vis ua l s ys tem m ay rema in a l ight w ithout f la sh ing o r pe rhaps s how a doub le s peed f la sh.

Veh icle re gu la t ions do no t s pe cify w he the r the te l l-ta i l s hou ld ind ica te funct ion o r fa i lure and a

manufa cture r can opt to in tegra te the te l l-ta i l o f the t ra i le r w ith the tow ing veh icle 's l ight cont ro l

s ys tem .

Tw in e le ct rics o r 13 p in?

Ea rly U K ca ravans had jus t one p lug w ith a co rre spond ing

socke t a t the re a r o f the tow ca r. The se w e re b la ck and had

seven p ins to pow e r the ca ravan 's road and inte rio r l ights .

In the m id to la te 1970s , a s fridge s , le is ure ba t te rie s and 12

vo lt e qu ipm ent be cam e more popula r, the need a rose fo r a

s e cond p lug and s ocke t . Ano the r fa cto r w as the la ck o f any

spa re p ins in the e xis t ing p lug and the le ga l re qu irement ,

from 1 O ctobe r 1979, fo r t ra i le rs to be f it te d w ith a re a r fog

l ight .

Ca ravans m anufa ctured from th is da te w e re f it te d w ith a gre y

p lug and le ad in add it ion to the b la ck one . The new p lug a ls o

had s even p ins but to avo id cro s s -p lugg ing the p ins w e re a rranged d iffe rent ly. A t th is t ime the

b la ck p lug be came know n a s the '12N ' (12 vo lt , no rma l) and the gre y a s the '12S' (12 vo lt ,

s upp lementa ry).

The ca ravan 's in te rio r l ights w e re now pow e red from the 12S p lug to a l low the fog l ight to be

pow e red from the 12N p lug . The advantage o f th is is tha t ca ravans can le ga l ly be tow ed by jus t

us ing the 12N p lug . O ne bonus o f the new 12S p lug is tha t it a l low ed ca ravans to be f it te d w ith

a re ve rs ing l ight fo r the f irs t t ime .

Fa s t fo rw a rd to Septembe r 1999 and s ome change s w e re made to the 12S w iring in a b id to

provide a be t te r s upp ly to fridge s , w hich w e re be com ing e ve r la rge r and requ iring more pow e r.

Th is change can cause compa t ib i l i t y p rob lems (e a s i ly re s o lvab le ) i f your ca r and ca ravan a re from

diffe rent s ide s o f th is da te .

A 13 p in s o cket o n a W es t faliato wbar w ith detachab le to wball

Fas t fo rw a rd aga in to Septembe r 2008 and U K bu i lt ca ravans

adopted the s ing le 13 p in p lug tha t had been s tanda rd on

the Cont inent fo r s ome yea rs . The 13 p in p lug and s ocke t is

gene ra l ly e ng inee red to a h ighe r s tanda rd than the o ld tw in

p lug s ys tem and is le s s l ike ly to be a ffe cted by p in burn o r

w a te r ingre s s .

Na tura l ly it w i l l ta ke a w hile fo r a l l ca ravans and tow ca rs to

adopt the 13 p in a rrangement s o adapto rs a re re ad i ly

ava i la b le tha t w i l l conve rt to and from the 12N , 12S

a rrangement . How eve r, i f you 're ge t t ing a tow ba r f it te d to

tow a ca ravan it w ould make s ense to go fo r the new e r 13

p in s ocke t .

12 N , 12 S and 13pin tow electricsw iring

12N w iring de ta i ls

Pin No C o nd ucto r C o lo ur Functio n

P in 1 Ye llo w LH in d ica to r

P in 2 Blu e Re a r fo g la mp

P in 3 W h ite C o mmo n re tu rn (e a rth )

P in 4 Gre e n RH in d ica to r

P in 5 Bro w n RH s id e ta il

P in 6 Re d Bra ke lig h ts

P in 7 Bla ck LH s id e ta il

12S w iring de ta i ls

12S w iring de ta i ls

Pin No C o nd ucto r C o lo ur Functio n fro m 1999 Functio n up to 1998

P in 1 Ye llo w Re ve rs in g lig h t Re ve rs in g lig h t

P in 2 Blu e No a llo ca t io n Ba tte ry ch a rg e

P in 3 W h ite Re tu rn fo r p in 4 C o mmo n re tu rn

P in 4 Gre e n In te rio r / ch a rg e In te rio r lig h ts

P in 5 Bro w n No a llo ca t io n No a llo ca t io n

P in 6 Re d Frid g e Frid g e

P in 7 Bla ck Ne g a tive (Fo r p in 6 ) No a llo ca t io n

13 p in w iring de ta i ls

Pin Functio n T yp ical C o nd ucto r C o lo urs

1 LH in d ica to r Ye llo w

2 Re a r fo g lig h t B lu e

3 C o mmo n re tu rn fo r p in s 1 , 2 a n d 4 -8 W h ite

4 RH in d ica to r Gre e n

5 RH re a r p o s it io n ,a n d e n d -o u t lin e lig h t, a n d re a r re g is tra t io n p la te Bro w n

6 Bra ke lig h ts Re d

7 LH re a r p o s it io n , a n d e n d -o u t lin e lig h t, a n d re a r re g is tra t io n p la te B la ck

8 Re ve rs in g lig h t P in k

9 C o n tin u o u s p o w e r s u p p ly O ra n g e

1 0 P o w e r v ia ig n it io n s w itch (u s e d fo r th e frid g e a n d h a b ita t io n re la y) Gre y

1 1 C o mmo n re tu rn fo r p in 1 0 W h ite /b la ck

1 2 Sig n a llin g co n n e ct io n to tra ile r (a la rms e tc) W h ite /b lu e

1 3 C o mmo n re tu rn fo r p in 9 W h ite /re d

The cen tre p in o f the 12S p lug iss et fo rward and is p ro ne to being

s quas hed o ver t ime

If the lo cking ring is no t lined up as here o n the left thep lug w ill no t go in to the s o cket

K now n issues w ith veh ic le tow ing system sNo tow ba r pre pa ra tion

Some veh icle s re qu ire tow prepa ra t ion a t the fa cto ry be fo re they can le ga l ly tow s o w e s t rong ly

re commend you che ck the veh icle V IN p la te to confirm it is s how ing th is tow ing capacity. Th is is

cove red e a rl ie r in Can the veh icle tow ?

M issing conne ctions

Some 12S and 13 p in s ocke t kit s f i t te d a t the ca r fa cto ry o r by ma in dea le rs a re no t fu l ly w ired

and may have conne ct ions , o r e ven p ins , m is s ing fo r the fridge and cha rg ing circu it s . Ge rman

ca rs s e em prone to th is p rob lem . Be fo re any w o rk is unde rtaken po int out tha t you 'l l be tow ing a

ca ravan and you w il l ne ed pow e r fo r the fridge and cha rg ing circu it s .

12S plug - fridge ove rhe a ting ce ntre p in

In 1999 the w iring o f the 12S p lug w as changed and the pre vious ly unused cent re p in (p in 7)

be came the e a rth re turn fo r the fridge . Th is means tha t i f you have a ca r w ith w iring be fo re th is

da te and a ca ravan from , o r a fte r th is da te , the fridge w il l no t w o rk w hile tow ing. The answ e r is

to e a rth p in 7 on the tow ca r.

The prob lem is tha t p in 7 is s e t fo rw a rd a l i t t le to he lp lo ca te

the p lug on ins e rt ion. In pra ct ice th is means the le ave s o f

the p in e ventua l ly ge t s quashed toge the r a s the p lug is

w igg le d from s ide to s ide during ins e rt ion and remova l. W hen

it ca rrie d no current th is d idn 't ma t te r but w ith 8 to 16 amps

depend ing on the s iz e o f fridge the re su lt ing poo r conne ct ion

can cause ove rhea t ing .

O ne w ay a round th is is to conne ct the cent re p in (p in 7) to

an unused p in and to do the s ame in the s ocke t . The current

is then sha red be tw een the tw o p ins and it doe sn ’t ma t te r i f

the cent re p in is a poo r conta ct s ince the o the r p in w il l ta ke

much o f the load .

P ins 2 and 5 a re no rma lly unused a lthough p in 5 is s ome t imes used by ca ravan a la rm s ys tem s . If

you de cide to pa ir p in 2 w ith p in 7 it ’s impo rtant no t to p lug the ca ravan into a ca r w ith pre -1999

w iring a s p in 2 w as used to cha rge the ba t te ry and w il l be l ive , re su lt ing in b low n fus e s .

Difficultie s inse rting 13 p in p lugs

A 13 p in p lug ha s a pos it ive lo cking ring

tha t needs to be ro ta ted to re ta in the

p lug . The prob lem is tha t , i f i t 's no t in the

right pos it ion, you w il l be unab le to ins e rt

the p lug in the f irs t p la ce .

The answ e r is to ro ta te the lo cking ring

fu l ly ant i-clo ckw is e (a s view ed w ith the

cab le po int ing tow a rds you) and then

ins e rt the p lug w ithout ro ta t ing the ring .

Ensure the p lug is w e l l a l igned be fo re

ins e rt ion, it s hou ldn 't be fo rced. Ho ld ing the p lug by the cab le can he lp he re .

A lte rna t ive ly a coup le o f dabs o f w hite pa int can be used to s how w hen the lo cking ring is

co rre ct ly a l igned fo r ins e rt ion - s e e pho tos .

Parking caps like th is o ne can be us ed to help line up the13 p in p lug befo re in s ert io n

The A L-K O s tab ilis er (left ) requ ires ex tra clearancearo und the to wball; the W in terho ff (righ t) do es no t

A L-K O 's ex tended neck to wball(left ) alo ngs ide a s tandard o ne

LED ro ad ligh ts can have co mpat ib ility p ro b lemswith s o me to w cars

Ano the r me thod is to l ine the lo cking ring

up us ing a pa rking cap. The se a re used to

ho ld the p lug w hen no t in us e and can be

purchased s epa ra te ly from ca ravan

acce s so ry s hops .

Neve r us e fo rce a s the p ins w ith in the p lug

can be pushed ba ck s uch tha t they make

poo r o r no conta ct w hen the p lug is

ins e rted .

AL-KO hitch he a d sta bilise rs

The coup l ing head on AL-KO 's h it ch head

s tab i l is e rs is qu ite la rge . To a l low it to

ro ta te fre e ly it is impo rtant to f it a tow ba l l

w ith s uff icie nt cle a rance be tw een the

cent re o f the ba l l and the ba se o f the ne ck,

and from the cent re o f the tow ba l l to the

nea re s t obs t ruct ion on the tow ing veh icle

e .g . bumpe r, to ensure co rre ct ope ra t ion.

Mos t sw an ne ck tow ba lls te nd no t to be a prob lem a s the re

is usua l ly p le nty o f room a round them but f la nge mount ing

type s can be . The answ e r is to us e an e xtended ne ck tow ba ll

s pe cif ica l ly de s igned fo r AL-KO s tab i l is e rs . W ith the se the

ba l l s it s h ighe r and furthe r aw ay from the mount ing f la nge

than w ith a s tanda rd type .

The W inte rho ff h it ch head s tab i l is e r ha s no such cle a rance

is sue s and can be used w ith a s tanda rd f la nge mount ing

tow ba ll. Equa l ly, non-s tab i l is e d h it ch heads can s a fe ly be

used w ith AL-KO type e xtended ne ck tow ba lls .

C a ra va ns w ith LED re a r lights

LED pow e red l ights us e on ly about one tenth o f the pow e r o f s tanda rd f i lament lamps . O ne

e ffe ct o f th is can be tha t the circu it te s t ing pu ls e s s ent out by s ome ca rs can cause a ca ravan 's

LED l ights to cons tant ly f l icke r. In o the r s itua t ions they may no t w o rk prope rly, o r e ven a t a l l .

The is s ue is tha t , unt i l you p lug the ca ravan into the ca r, you 've no w ay o f know ing w ha t w il l

happen. Gene ra l ly s peaking ca rs tha t have LED re a r l ights don 't have prob lems but the re 's no

gua rantee . Y our tow ba r f it te r may have more in fo rma t ion.

I f you have th is p rob lem , consu lt your ca ravan

dea le rsh ip . They may be ab le to he lp you s ource

a mod if ica t ion kit from the ca ravan manufa cture r

o r the w iring loom supp l ie r. The se can be ca r

spe cif ic s o make sure you have e xa ct de ta i ls to

hand.

Iron ica l ly ca rs w ith bypas s e le ct rica l s ys tems a re

un l ike ly to have prob lems a s the ca ravan 's l ights

a re no t m onito red by the ca r's compute rs . The re la ys s imp ly a ct a s sw itche s and it ma t te rs l i t t le

w ha t type o f bu lb is on the o the r end. How eve r the se w il l no t in t regra te in to the ca r lamp

w a rn ing s ys tem .

'Sma rt' a lte rna tor te chno logy

To com ply w ith incre a s ing ly s t ringent em is s ion regu la t ions veh icle manufa cture rs have employed

increa s ing ly cle ve r te chno log ie s . O ne tha t is now be com ing s tanda rd on new veh icle s is the

'sma rt ' ECU -cont ro l le d a lte rna to r.

Ins te ad o f the output be ing de te rm ined by a s imp le vo ltage regu la to r, the a lte rna to r is

cont ro l le d by the ca r's ECU in a w ay tha t ba lance s e le ct rica l load w ith eng ine e ff icie ncy. W hen

the ba t te ry doe s no t need cha rg ing the a lte rna to r may be shut dow n to reduce eng ine load.

Depend ing on the w iring and type o f the re la y in the tow ca r the output to the ca ravan 's fridge

and cha rg ing circu it s may a ls o be s hut dow n. A tempora ry s o lut ion is to sw itch on d ipped

head l ights to fo rce the a lte rna to r to produce pow e r.

A longe r te rm so lut ion is to ensure the re la y ope ra te s via an auxi l ia ry conta ct on the ign it ion

sw itch a lthough th is doe s mean the ca ravan ba t te ry be comes conne cted to the ca r ba t te ry w hen

s ta rt ing the ca r. It a ls o means the ca ravan 's fridge can dra in bo th ba t te rie s i f the ign it ion is le ft

on w ithout the eng ine runn ing . How eve r, in p ra ct ice and w ith a l i t t le ca re , the se is s ue s a re no t

no rma lly a prob lem .

Softw a re upda te s

A n A L-K O to wbar and chas s is

Leg is lat io n has s een o ff theus e o f d ro p p lates in many

circums tances

W hen a veh icle s pe cif ic-w iring kit is f i t te d the ca r's e ng ine management s o ftw a re is

reprogram med a cco rd ing ly. Shou ld the veh icle s ubsequent ly unde rgo a s o ftw a re upda te , w hich is

ve ry l ike ly during a rout ine s e rvice , it is pos s ib le fo r th is add it iona l p rogramm ing to be w iped

out . Apa rt from pe rfo rmance is s ue s th is can mean annoying th ings l ike the re a r pa rking s enso rs

cont inu ing to ope ra te w hen the ca ravan is conne cted . The answ e r is to ensure your dea le r is

aw a re tha t a veh icle s pe cif ic-w iring kit ha s been ins ta l le d be fo re ca rrying out any upda te s . It s

w o rth no t ing tow ba r f it te rs a re aw a re o f th is is s ue and shou ld be ab le to reprogramme the

veh icle to a ct iva te the funct ions .

O ther tow bar considerationsT ow ba rs for motorhome s

Mos t mo to rhom es can be f it te d w ith a tow ba r but re a r

ove rhang and l im ited s pa re pow e r may re s t rict w ha t can be

tow ed. Mo to rhomes m ay be bu i lt e nt ire ly on the unmod if ie d

chas s is o f the ba se veh icle , o r on s uch a cha s s is w ith cus tom

made extens ions o r on a veh icle w he re the o rig ina l cha s s is

ha s been com ple te ly re p la ced by a th ird pa rty product , s uch

as the AL-KO AMC chas s is .

A s ment ioned in the int roduct ion, a l l mo to rhomes f irs t

re g is te red from 29 O ctobe r 2012 fa l l unde r the s cope o f EC D ire ct ive 94/20 and more re cent ly

unde r ECE Regula t ion 55. Th is means tha t s uch veh icle s mus t have a type approved tow ba r

ins ta l le d; cus tom made tow ba rs a re no longe r s u itab le and w il l cause an MO T fa i lure .

Tow ba r m anufa cture rs have ris en to the cha l le nge such tha t a w ide range o f tow ba rs is now

ava i lab le fo r the se new e r veh icle s . How eve r, e a rl ie r mo to rhomes may s t i l l have the opt ion o f a

pre -approva l re ady-made tow ba r from the l ike s o f AL-KO and it s s ubs id ia ry Saw iko w hich

manufa cture s tow ba rs fo r veh icle s w ith and w ithout frame extens ions , and o f cours e fo r those

w ith the AMC chas s is .

W he re no proprie ta ry tow ba r is a va i la b le a cus tom made one can be s t i l l be f it te d to

moto rhom es reg is te red prio r to 29 O ctobe r 2012 but the C lub s t rong ly re commends the de s ign

and eng inee ring e lements a re ca rrie d out by a company tha t s pe cia l is e s in s uch w o rk.

Fo r more in fo rma t ion on th is top ic s e e the C lub 's Da ta Shee t # 25 - Tow ing w ith a mo to rhome .

Drop p la te s

Drop p la te s mus t no t be used on EC approved tow ba rs un le s s the

tow ba r ha s been subm it ted and te s ted fo r EC Type Approva l us ing

a drop p la te a s it adds much more load to the tow ba r mount ings

and may damage the tow ba r and the tow ca r. Some 4x4 tow ba rs

a re te s ted in th is w ay. The manufa cture r w i l l know if th is is the

ca se . U nde r no circums tance s s hou ld a drop p la te e ve r be used to

ra is e the he ight o f a tow ba l l.

Shock a bsorbing couplings

Many yea rs ago tow ba r manufa cture r D ixon Ba te produced the Shockl ink coup l ing . It us e s co i l

s prings w ith rubbe r ins e rts to abso rb any shocks t ransm it te d through the tow ba r to the t ra i le r.

The coup l ing is p rima ri ly de s igned fo r us e on 4x4s and o the r la rge veh icle s f it te d w ith le a f s pring

rea r s uspens ions .

The D ix o n B ate S ho cklink Mark II

The Shockl ink w as on ly ava i la b le fo r veh icle s f it te d w ith a

D ixon-Ba te ad jus tab le he ight tow ba r. It can 't be used w ith

o the r type approved tow ba rs un le s s the tow ba r ha s been

granted type approva l w ith the Shockl ink in p la ce . I f you can

s t i l l f ind one it can be f it te d to ca rs reg is te red be fo re 1

Augus t 1998 and moto rhomes reg is te red be fo re 29 O ctobe r

2012.

R elated C lub D ata S heets and other usefu lpublications

Da ta s hee t 20 - Ma tch ing ca r and ca ravan - P ra ct ica l advice on s a fe and com fo rtab le tow ing.

Da ta Shee t 21 - Sa fe fo r the road - s a fe on the road - Important s a fe ly fa cts to cons ide r

be fo re you s e t o ff.

Da ta Shee t 22 - Stab i l is e rs and t ra i le r cont ro l s ys tems - an e xp lana t ion o f s tab i l is ing a ids

and how they w o rk.

Da ta Shee t 25 - Tow ing w ith a mo to rhome - Th ings to cons ide r i f you 're th inking o f tow ing

w ith a m o to rhome .

Ca ravan Tow ing Guide (ava i la b le from the NCC 's w ebs ite - w w w .thencc.o rg .uk.

If you ha ve fe e dba ck on our ne w forma t Da ta she e t, p le a se le t us know , using our short

Fe e dba ck Form.

G lo ssaryG lo ssary

ABSABS

Ant i- loc k braking sy s t em - a sa fe t y sy s t em t ha t prevent s t he w hee l s from loc king during braking. T his he lps t he

t y res t o ma int a in a good grip on t he road surfac e .

EC UEC U

Engine c ont ro l unit o r e le c t ronic c ont ro l unit . T his is t he c omput e r t ha t c ont ro ls t he engine and o t he r func t ions on

a mode rn c a r.

ESPESP

Ele c t ronic s t ab ilit y programme - a so ftw are programme built int o many mode rn c a rs t o improve handling by

de t ec t ing and reduc ing any loss o f t rac t ion. It may a lso be know n as dynamic s t ab ilit y c ont ro l (DSC).

Gross Train W eigh t (GT W )Gross Train W eigh t (GT W )

T he maximum an out f it , suc h as a c ombina t ion o f a c a r and c a ravan, is a llow ed t o w e igh w hen fu lly loaded.

H itc h h eigh tH itc h h eigh t

T he he ight o f t he c ent re o f t he t ra ile r c oupling hit c h in milime t re s above ground w it h t he out f it le ve l, f ront t o bac k.

It should be in t he range 395mm t o 465mm.

Kerbw eigh t/ M ass in Run n in g O rderKerbw eigh t/ M ass in Run n in g O rder

T he ke rbw e ight is t he M ass in Running Orde r (M IRO) o f a c a r. T his is de f ined in European Dire c t iv e 95/48/EC as t he

“mass o f t he vehic le w it h bodyw ork in running o rde r ( inc lud ing c oo lant , o ils , fue l, t oo ls , spa re w hee l and drive r)”.

How eve r, some c a r manufac t ure rs do no t inc lude t he w e ight o f t he driv e r (75kg) in t he ir ke rbw e ight f igures .

M ass in serv ic eM ass in serv ic e

T he M ass in Running Orde r (M IRO), o r ke rbw e ight inc lud ing a 75kg drive r, o f a c a r as it le ft t he fa c t o ry . It exc ludes

any c omponent s added by t he dea le r. T his f igure is g iven in t he c a r’s Vehic le Regis t ra t ion Ce rt if ic a t e V5C (‘log

book’) fo r new er vehic le s .

M axim um Auth orised M ass (M AM )M axim um Auth orised M ass (M AM )

A lso know n as M aximum Gross W e ight (M GW ) or Gross Vehic le W e ight (GVW ). T he maximum a vehic le is a llow ed t o

w e igh w hen it ’s fu lly loaded.

M axim um Tec h n ic ally P erm issib le Laden M ass (M T P LM )M axim um Tec h n ic ally P erm issib le Laden M ass (M T P LM )

T he M aximum Authorised M ass (M AM ), norma lly applied t o a c a ravan

N osew eigh tN osew eigh t

T he s t a t ic dow nforc e t he t ra ile r put s on t he t ow ba ll o f t he t ow ing vehic le .

Tow ball h eigh tTow ball h eigh t

T he he ight from leve l ground t o t he c ent re o f t he t ow ba ll w hen t he vehic le is fu lly laden. It should be in t he range

o f 350mm t o 420mm.

Tow in g lim itTow in g lim it

T he maximum w e ight a vehic le is des igned t o t ow up a 12 pe r c ent h ill (1 in 8).

T SPT SP

T ra ile r s t ab ilit y programme - a fea t ure built int o some vehic le s t o de t ec t and reduc e t he 'snaking ' a c t ion o f a

t ra ile r, should it oc c ur.

C o ntactsC o ntacts

W eb :W eb : AL-KO

M anufac t ures t ow bar sy s t ems des igned spec if ic a lly fo r use w it h t he AL- KO c hass is andc hass is ext ens ions as found on many mot orhomes.

W eb :W eb : Bosa l Group

A lso famous fo r it s exhaust sy s t ems t he Bosa l Group is Dut c h reg is t e red but headquart e red inLummen, Be lg ium.

W eb :W eb : Brink Group

Ac quired by t he T hule Group in 2006 t he c ompany is now a s t anda lone ent it y , headquart e redin Ho lland.

W eb :W eb : PCT Automot ive

Based a t Ho lbrook, nea r She ff ie ld and has an enginee ring he rit age da t ing bac k t o 1926.

W eb :W eb : Tow -Trus t

Based in A t he rs t one , W arw ic kshire t he c ompany w as founded in 1991 w it h t he ambit ion o fsupply ing t he 'h ighest qua lit y ' produc t s t o t he t ow ing marke t .

W eb :W eb : W at l ing Eng inee rs

Loc a t ed c lose t o S t A lbans t he c ompany spec ia lise s in produc ing bespoke t ow bars fo r vehic lew he re c omplianc e w it h t he d ire c t iv e 94/20 is no t required.

W eb :W eb : W es t fa l ia Automot ive

Credit ed w it h t he invent ion o f t he t ow bar and t ow ba ll in 1932, W est fa lia has beenmanufac t uring t ow bar sy s t ems eve r s inc e . Based in Ge rmany , t he c ompany has a d is t ribut ionand f it t ing c ent re in Bris t o l.

W eb :W eb : W it te r Tow ba r Sys tems

F ormed in 1950 by Co lin W it t e r t he c ompany has s inc e bec ome one t he UK's lead ing t ow barmanufac t ure rs from it s mode rn fac t o ry in Dees ide , nea r Chest e r.

W eb :W eb : Na t iona l T ra i le r & Tow ing As socia t ion (NTTA)

F ounded in 1975 as t he A ssoc ia t ion o f T ra ile r M anufac t ure rs , t he NT T A is t he t rade body fo rt he t ow ing indust ry . It s w ebs it e c ont a ins muc h use ful adv ic e on sa fe and lega l t ow ing.

W eb :W eb : The Camping and Ca ravanning C lub

Greenf ie lds House W estw ood W ay Covent ry CV4 8JH

ht t ps://w w w .c ampingandc a ravanningc lub.c o .uk

Tel:Te l: 024 7647 5448