Tow Hitch Wiring Guide for P2 Volvo V70, and probably S80 and S60s | SwedeSpeed

I spent a lot of time researching the forums regarding tow hitch wiring on my 05 V70 2.5T but left very confused. There was an official way to get the tow hitch wiring right into the chassis harness. However doing it officially is insanely expensive. It was roughly 100 for the wiring, 90 for trailer wiring controller, 80 dollars for the software and an hour of labor at the dealer to install it. So $400 for hitch wiring! Crazy.

I decided to test out one of the universal wiring kits that was suggested to me by Curt. And I found out it works with no codes or burnt out bulbs. I have yet to take it for a long trip but hooking up my jetski trailer showed it working and no burnt out lights on the DIM. Its very simple to install but it takes some time. I assume this will work with S60s and S80s but there may be a difference in color of wires but I am not sure. Etrailer.com makes an install video for S60s.

I used a CURT 56496 Weather-Resistant Powered 3-to-2-Wire Splice-in Trailer Tail Light Converter, 4-Pin Wiring Harness

They neglect to include an inline 10 amp fuse with a ring connector (which of course they mention you need), they offer that as a 10 dollar add on but I had one laying around at my parents.

I set up my wiring on the driver side little cubby behind the rear wheel well, that has the little pull out section. I had to remove a lot of the wiring to properly get the wire colors but if you know ahead of time you wont have to do this. I have included some photos of the correct wire colors. I also created a chart at the bottom to reference so you don’t have to pull your interior apart to test colors. You will only have to get to your battery along with the two covers on corners of the cargo area.

I mounted the controller next to the fuse box and ran power and ground to the battery right by the fuse box. There is a ground right behind the battery on the body of the car and I just ran the ring connector the the spare bolt on the positive terminal of the battery.

Positive has the blue heat shrink and negative is the white cable (white is negative on the curt controller)

So now regarding connections. On the driver side, green is left turn signal which goes to yellow on the brake controller.

On the passenger side, green with a white stripe is turn signal which goes to green on the brake controller.

Yellow on the car is brake, which goes to red on the controller.

Grey with white stripe is tail which goes to brown on the controller.

So to recap.

Car Side Cable Color : Trailer Controller Side Cable Color

Driver Side Green Turn Signal : Yellow
Passenger Side Green w/ White Stripe Turn Signal : Green
Driver Side Yellow Brake : Red
Driver Side Grey w/ White Stripe Brake : Brown

If anyone has any questions please feel free to send a PM. Will update with more questions if any come up.