Wierd electrical fault - where do I start ?

[RoryRover]

Hello all - sorry about the long post - but this is just wierd !

I have had my 75 tourer for a month and it came fitted with a towbar and 13 pin socket. On Monday I had to pick up a car trailer ( the first time I have towed with the car) , and knowing that the trailer only had 7 pin electrics I brought a 13 to 7 pin converter in advance.

Before leaving home I fitted the adaptor, jumped in the car, and then saw the "bulb" failure light stay on which has never hapened before. Checking the lights showed everthing worked until I tried the right indicator, at which point it began to flash at twice the normal rate. From outside the car the rear indicator and side repeater were flasing quickly, but the front was not.

I then removed the 7 pin adaptor to see what happened - and even with it removed the fault remained. I then presumed the front indicator bulb had failed - so I decided to pick up the trailer as I could get a new bulb while there. Off I set (without the 7 pin adaptor fitted) and after about 3 miles the warning light went off and the right indicator started working normally again.

By now a little confused I stopped just before I reached the trailer hire depot and re-fitted the 7 pin adaptor. No problem - right indicator continued to work normally. Then I connected the trailer, and again checked all the lights and everything worked normally.

Everything worked normally as I drove home, and when I got home I disconnected the trailer while it was parked overnight. Next morning I re connected the trailer and again everything worked normally, and continued to work normally on a 70 mile drive to Cadwell Park with a golf GTI race car on the back ( about 1400kg total load - towed superbly).

I did not need to disconnect the trailer at Cadwell park, but when I started the car at the end of the day the bulb failure light came back on. Again all the lights worked normally except the right hand indicator, and again it was the front indicator that did not flash - the one on the trailer did.

I had to drive home. and hoped the fault would clear iteself again - but no such luck, and I have now driven the car today without anything connected to the tow socket but the fault persists. I have obviously replaced the front indicator bulb with a new one, but it still does not flash.

So where do I look now ? Are there any car electrics experts out there who could advise me how to trace and fix the fault ?

[stocktake]

first thing to do is clean the contacts that the bulb sits on and then the earth connection I don't think the 13 to 7 pin adaptor has any bearing on the matter.

[75.0]

Hi John, do you have a 7 way bypass relay fitted? modern vehicles with bulb failure monitors need them. If one is fitted and your front indicator bulb and connector are ok, try disconnecting the battery for a couple of minutes

[HarryM1BYT]

It sounds as if he has the proper Can-bus towing unit fitted. Mine became very confused when I first installed it and connected a trailer for the first time. It disabled the reversing sensors (as it should), but then didn't re-enable them when the trailer was disconnected. It did eventually sort itself out and has subsequently worked fine.

If you have the IPK fitted, from memory, it will say something like a trailer lamp has failed, then mention the actual circuit with the failed lamp.

[RoryRover]

Hello all

Problem now fixed - it turned out to be a poor connection in the main plug on the passenger side that connects the electrics in the front bumper.

Disconnected and reconnected it a few times making sure it was fully seated and bingo - everything now works as it should.

Thanks for the advice.

[Zeb]

Nice dog....