2005 v-8 XC90. We have a Volvo only repair shop but no Volvo dealer in our area. We purchased a pop-up camper to tow with the XC90. I originally asked this shop which I have used for years to install trailer wiring. I was told "that.s not really our forte, have a trailer shop install the trailer wiring". The trailer wiring worked fine for the first 2 short trips. Hooked up last week-end and shortly after, windows quit working, radio had static noises, and "overcharging stop vehicle" warning came on. I understand the window, radio, warning thing. My shop installed Volvo alternator and no more warnings on the dash. My shop is telling me now that only a Volvo trailer wiring can be used, and that's caused the whole problem. Complete factory wiring, module, software update, etc, $600,00 plus labor. It may be best in my situation to just spend the money now, so that if I have any other issues, the trailer wiring won,t be questioned. Your input would be appreciated. Anyone have an extra Volvo wiring kit for sale? Best Wishes gjones

 

I just purchased an 60 2.5t FWD with a u-haul installed trailer hitch and wiring installed. It sounds to me as though the installation was botched. The hot wire for trailer wiring should/ could come straight off the battery and fused. The running lights, brake light and left turn signal cane be accessed on the drivers side then a wire extends to the passenger side to bite off of the right turn signal. Very simple system. Where it may get complicated is if the pop up has electric brakes if that is so your shop may be correct and the money would be well spent in my opinion.

 

Sorry you're having issues, bummer!

I installed trailer wiring on my 2005 XC90 2.5t. For me it was simply plug and play. The harness I used is made by Curt and I bought it on Amazon.

https://amzn.com/B0031GAJC4

The tail light wiring on my XC90 has quick connectors so no splicing, cutting, wire stripping, etc. It went together surprisingly well.

Now, that only got me the typical flat style 4 wire connector. If you're setup is more complex I'm afraid I'm not much help with that.

Oh and just my opinion but screw that dealer fee. The part cost me $45 and only took 45 minutes to install. That price is crazy.

PS...check the ground wire. If they didn't do a good job finding a good ground that can cause all sorts of issues. I grounded mine right to the body of the car. It involved drilling a hole, but it's inside the cab behind the rear paneling so no biggie.

 

We have the parts you need in stock:

30756529 HARNESS 1 0 0 172.83 137.33
30664974 CONTROL U 1 0 0 105.67 83.22

Tim
800.234.5394

 

I just added this to my 05 XC90 2.5t, The directions that came with my wire kit, stated to use the Fuse box positive screw/nut. I have hoped that this process will have allow the box to be in an off mode, when the key is off.
Fits 2005-2014 Volvo XC90 :
Curt Trailer Hitch 13559 Class 3,
Wiring 56045KIT
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1