I have an installed volvo wiring harness. I do not know who wired it. I purchased the car used. The used car dealer I purchased the car from, bought me the Volvo convertor 7 to 4 wire from Volvo andI plugged it in.The lights are not right on my trailer. I unplugged the convertor to see what the car was sending but I do not know how the car is wired. The trailer worked on my old car and another trailer worked on my old car so I figure it is wired right. Does anyone have the wiring diagram on how the car is supposed to be wired to the 7 pin connector?

 

No but you can get a multimeter and check for yourself where the signal is going. And it may be that the adapter isn't quite right. I just got a cheap 4 pole wiring kit from auto zone and put that in to bypass the 7 pole. Much easier and cheaper