I connected a cable set for the trailer coupling to the rear lights and mounted two relay-boxes in the trunck. I followed the instructions.
When I open my car with the wireless key the indicator blink once and I can here the new relay-box click, but when I lock the car the indicators don't blink at all and the
relay-box is not clicking. Everything was working fine before I connected the cable set.
When I connected the wiries as they were at the beginning the indicator is still not blinking three times when locking.
Could that be a broken relay?

 

but the doors locks?

 

Yes, the doors locks.

 

i don't understand what relay you put on it.

it should ba a trailer recognition module.

may i have you VIN number?

 

I put two modules. One is a CC-module with yellow label and the other is a AFC module with red label on it. The modules where part of a kit I got from Mercedes.

Where can I find the VIN number?

 

lower area of windshield, driver's side. something like: WDB 202*** ** ******


i think nothing is wrong with your wiring since it blink once while unlocking.

the wiring that you have added is simply to make the trailer lights work...such as turning, braking, reversing and tail lamp. it cannot control any internal lights.

only if you have made a mistake, the the front SAM or fuse control unit could get damage... but not likely.

 

Now it works. Stupid me! I have not fitted the panels in the trunck yet so the switch for the trunck door is not activated when door is closed.

 

i was wondering also since my first question was if the door locks.

have a nice day. it's been a month but you finally did it!

 

Thanks a lot!