OK so I ponied up for the actual Volvo wiring harness for my trailer. It terminates in a flat-four connector (standard for light trailers) and does the "4-bulb to 3-bulb conversion" (i.e. the brake lights and turn signals are on the same filament). And it worked great for a couple of months even including lighting up the auxiliary turn signal light on the lower right side of the dashboard. But now it doesn't work at all. It's not a problem with the trailer, I tested it with a tester also. Any suggestions? How about a pinout for the connector near the spare tire so I can see whether the problem is the car not sending signals to the adapter or the adapter not passing them through to the external connector...

Thanks!

I have checked out the car a bit more...the factory wiring harness in the car is making the correct signals. Also the running lights are actually working, only the turn/brake lights don't work.

If I feed +12V and GND to the appropriate pins in the adapter harness (Volvo p/n 8698079-4) I can get the running lights to come on (just like the car can). But I can't get the turn signals or brake lights to work. So it looks like the adapter is fubared.

It has a 1-year warranty so I'll contact the shop I bought it from. The only fly in the ointment is that I need to to a trailer to Tennessee in 2 weeks, I hope I can get a replacement by then.

I would think it is the connetion between the box and the car wiring. One of the splices might have come loose, those are pretty small wires. I have the same box on my 854 and no problems.

Klaus
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Please answer, we need to know if the advice is good or bad. The 164 has a new home, all I am left with are 2 turbos :)