tow bar/rear lights wiring colours.

750FLYER

Registered User
Hi all,

Audi A4 B7 Avant:

I'm wiring a new tow bar in today. I know which coloured wires from the 7 pin plug do what.. see diagram:

12N_Socket_wiring.GIF


However I do not know which coloured wires in the rear of the car match up to these.. Can anyone tell me, or put up a nice easy diagram to show me so I can splice this baby in... It's only a single electric so I won't be using a relay.

Cheers in advance :confused:
 

Cyrix

Registered User
You will need a 7 way bypass relay for single electrics, simply tapping into the wiring will not work it will set off various bulb warnings.

As for which wires to use, can't remember. I used a multimeter to work out which wires to tap into.
 

750FLYER

Registered User
You positive about that relay mate? I've never used a relay on any of my previous cars for single electrics...
 

SootySport

Registered User
Towbar companies use a magic box to stop bulb errors (some sort of relay I guess) and to give the extra indicator beeping when towing. Yes, it's not as quite straight forward as it used to be.
Having a guy fit a tow bar on the S4 Wednesday, £360. Audi wanted £1800 :tapedshut: apparently 8hours just to do the wiring.
 

750FLYER

Registered User
Jeeez!!

Well it took me most if yesterday to pull the entire back end off the friggin car just to attach the tow bar, it's all on now and I just need to do the wiring, can't put the rear interior back together again til it's done so looks like I need this relay asap... should be simple to wire in I think once I get it................

Still searching for those wire colourings tho anyone?????????????????????
 

SootySport

Registered User
Yes, you'll need to know what wires go to what lights before you fit a the relay box. Sorry I can't help on this new fangled stuff, if the car was pre 70's it would be a doddle, I'm a whizz on them.
 

I'm Just Rob.

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Jeeez!!

Well it took me most if yesterday to pull the entire back end off the friggin car just to attach the tow bar, it's all on now and I just need to do the wiring, can't put the rear interior back together again til it's done so looks like I need this relay asap... should be simple to wire in I think once I get it................

Still searching for those wire colourings tho anyone?????????????????????


yep, they do take a while, i spent my afternoon off plus some of the evening doing mine.
I do have a diagram somewhere, i think it may be on my old laptop, i'll power it up and have a look, in the meantime i'm sure there are details on this b7 section somewhere, maybe try a search for towbar electrics etc and see what pings up.

if i can find it later i'll ping you with the details etc.
rob
 

750FLYER

Registered User
Rob cheers that'd be excellent.. I will have a search too. .Yep pretty much the entire boot interior had to come out, total pain in the butt!! When I get the correct wires sure will be pretty easy to finish up now
 

SootySport

Registered User
had my towbar fitted and the engineer says you need the 7 way relay. You'll also need a permenant live feed to the relay, he used the 12v. socket in the boot.
 

750FLYER

Registered User
Used the live feed in the boot ta... Wiring was doing my head in so got a local auto-sparks bloke to come over. £60 so with £91 for the towbar was £150 all in.......

Except for 6 hours fitting the towbar myself.. not really worth it unless you have plenty of time. I'm happy now tho!

Snetterton in 2 weeks..... BRING IT ON!! :rockwoot:
 

SootySport

Registered User
Well that was a mission :). That cost you about half the all in price for an independent towbar man, so dosh saved for your trackday, have fun.
I bit the bullet and went for the detachable tow hook and fold up electric socket, looks good but did cost £483 :eyebrows: in the end, one trackday less for me this year.
 
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750FLYER

Registered User
Detachable's good tho... The ****** whole thing adds considerable weight to the car....... Good job it's not the racer that'd add 3 seconds a lap I reckon! :jester:

Fold-up socket indeed....! Flash git.. Ha ha. Nice one good luck back on the track, Are you a car or bike racer?
 

I'm Just Rob.

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detachable with flip up socket is great:cool:, its really nice not having that lump of steel stuck out the back all the time, seconds to fit the neck and pull down socket , job done:icon thumright:, glad you got yours all sorted.
good luck with the track day:icon thumright:
 

SootySport

Registered User
Detachable's good tho... The ****** whole thing adds considerable weight to the car....... Good job it's not the racer that'd add 3 seconds a lap I reckon! :jester:

Fold-up socket indeed....! Flash git.. Ha ha. Nice one good luck back on the track, Are you a car or bike racer?

Clue in my signature,
 

750FLYER

Registered User
Ah I see..... Gee that's a lot of wheels to have to contend with.. I get confused after 2!! :shrug:

Cheers and g'luck all
 

SootySport

Registered User
My mate has just taken delivery of a new Mondeo estate and he has an electrically operated tow bar, just push a button in the boot and the tow bar magically swing out, :cool:
 

SootySport

Registered User
Ah I see..... Gee that's a lot of wheels to have to contend with.. I get confused after 2!! :shrug:

Cheers and g'luck all
Yep, a few wheels, have 3 sets for the Westfield as well.
 
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