[Solved] Audi A4 B5 avant, Hook module, - short circuit of the trailer turn signals

Hello, I have a problem with the trailer socket. Everything shines ok except for the turn signals, which when selected on one side give voltage to both sides simultaneously and additionally cause a short circuit when I have a trailer attached. Without a trailer, the direction indicators in the car work flawlessly.

Walking on the cable I got to the relay / module (photos). And I think there is a problem here. When I turn on, for example, the left turn signal, the voltage appears on 6 out of 8 wires. Should this relay / module work like this or give only voltage to 3 wires, e.g. R or L. I will add that the board looks like fine and does not smell of burning. Please help.

The second unknown for me are the additional 3 cables in the socket that are not connected to the plug but in the housing itself. In the attached photo they were plugged into the white part that has no transition to the trailer plug but "sinks" in the housing.

xmaciejox wrote:

The second unknown for me are the additional 3 cables in the socket that are not connected to the plug but in the housing itself.

This is a microswitch that disconnects the fog lights in the car when the trailer is attached.

xmaciejox wrote:

Without a trailer, the direction indicators in the car work flawlessly.

And does the trailer lighting work properly with another car?

Yes, the trailer is ok, checked many times on another car. The problem is definitely with me because even the meter confirms the voltage on both cables, both left and right at the same time

xmaciejox wrote:

The problem is definitely with me because even the meter confirms the voltage on both cables, both left and right at the same time

It is possible that the module is not working properly.
I am sending you a similar topic. You can try to skip the module by plugging in jumpers like the topic.
https://www.elektroda.pl/rtvforum/topic960188.html#16792819

Extra, I'm testing tomorrow and I'll let you know


Problem solved, connecting the cables as in the answer above proved that the module is faulty. For now, the directions are working, however, you can see heavy loads for the lights that dim slightly, also in case someone has the said module, they will be happy to buy it back. Thank you kindly for your help

Problem solved, connecting the cables as in the answer above proved that the module is faulty. For now, the directions are working, however, you can see heavy loads for the lights that dim slightly, also in case someone has the said module, they will be happy to buy it back. Thank you kindly for your help