7 pin trailer connector

[hansbenade]

I bought a 2006 X5 3.0d with a tow hitch and 7 pin connector fitted. The problem is the tail lights of the trailer does not come on. I traced the wiring back to a small black box in the spare wheel well, and found there is no output for the tail lights. The installation is aftermarket - spliced into the existing wiring. I read that the X5's tail light and brake light is one single filament lamp, the voltage is lower for tail lights and full power when the brakes is applied. Maybe the small black box is defective, but I can't find a replacement. Does anybody know of a workaround?

 

[hansbenade]

I bought a 2006 X5 3.0d with a tow hitch and 7 pin connector fitted. The problem is the tail lights of the trailer does not come on. I traced the wiring back to a small black box in the spare wheel well, and found there is no output for the tail lights. The installation is aftermarket - spliced into the existing wiring. I read that the X5's tail light and brake light is one single filament lamp, the voltage is lower for tail lights and full power when the brakes is applied. Maybe the small black box is defective, but I can't find a replacement. Does anybody know of a workaround?

Auto-electrician traced the problem to a burnt track in taillight controller box, 2 minutes with a soldering iron - fixed. Still have to install an in-line fuse.