Towing electrics problems?

**convertvw** · 28-01-2010, 02:36 PM

Was out buying a trailer to drag across the Nullarbor behind my '08 Passat wagon and the trailer bloke mentioned problems with VW compatability with LED trailer lights and rear parking sensors not disconnecting - anyone had any experience with this?

Sensors and tow kit with 13 pin connection are factory fitted and the local VW place doesn't have adapters, anyone know if an auto shop adapter will be ok or do I need the genuine article to ensure all goes well?

appreciate any experiences/recommendations but I ain't no technician so the simpler the better!

**Swallowtail** · 28-01-2010, 02:39 PM

I'll move this thread to the Passat forum - this is for car audio etc.

As to the issues - yes you may have problems. LED trailer lights can cause issues - I have standard bulbs in mine so can't help you with that one though.

The rear parking sensors - if they activate when the trailer is connected then the car needs to have some coding changes so that the electronics know when you have a trailer on board. If it is done properly then you will not have any issues - on mine, when a trailer is connected the rear sensors disable, and the Optical Parking System comes up with a picture of a trailer. See your dealer to sort that out if it is not the case.

Your tow kit should have come with an adapter cable about 300mm long that goes from the 13pin round to the Aus 7 pin flat. Again, if you don't have that then your dealer should be able to supply. The adapter cable has some diodes in it, it is not just a straight wire swap.

**Rocket36** · 28-01-2010, 03:49 PM

The problem with LEDs is they draw far less current than standard bulbs so the car thinks they're not working and disables them.

Make sure you buy LED lights with the built in resistors that immitate the current of standard bulbs.

Not sure regarding trailers but it's possible if the car senses there isn't enough current being drawn it may decide not to send power to the trailer electic system.

**tryingavw** · 28-01-2010, 04:19 PM

Originally Posted by Rocket36

The problem with LEDs is they draw far less current than standard bulbs so the car thinks they're not working and disables them.

Make sure you buy LED lights with the built in resistors that immitate the current of standard bulbs.

if you have the LEDs without resistors you can fit external resistors across them as well.