Just joined! But I’m about an hour from cutting into my factory wiring harness 😭 So I could use help ASAP!

I have a curt adapter but still have to find the correct wires for signal. I took a peak at the wrapped bundle to the tail lights but I didn’t start unwrapping.

Lomg story short, I’m taking my S60 on a 12k Mile Road trip and have a cargo carrier, the carrier has a 10” riser from a class 3 (2”) hitch making it 17” off the ground. I’ll be using a 24”x24”x60” softbox, so it covers the tails, signals, and plate, so to avoid unwanted attention and to be as safe as possible, I modified the cargo carrier to have trailer lights. Finished wiring the carrier last night at 4:30AM, ready to start on the car. I do know I’ll need to run power from the battery to the trunk. I’ve installed audio systems in previous cars, so I feel quite comfortable doing this. Any help appreciated!

 

 

 

I am not a mechanic, so take this with a grain of salt, but this is what I've read and my experience to the best of memory.

So I'll mention just in case you're not aware, the proper way to wire in a trailer hitch is to buy the 300 dollar module volvo makes for the car. I mention this also because I believe it disables the awd for towing, which might be important if you try to tow something in the future as it may cause damage to the awd system. My t5 also has I believe a 300 lb tongue weight limit, so if you fill that carrier plus the back of the car you may be overloaded, which again may be hard on the awd.

I have no options on my t5 so I just wired the curt 4 prong adapter into the tail lights. My neighbour at the time was a mechanic so he tested it before actually cutting anything to see if it would throw the computer for a loop.

These cars are so sensitive, for example with the left rear taillight unplugged the dash threw a brake failure warning, and when I turned off the car it wouldn't turn back on until I plugged the electrical back in.

That being said I have towed a small open trailer with the wiring tied into the brake light wires with no ill effects. Never popped a fuse and the car doesn't seem to have any voltage issues.

If memory serves correct the tail lights/brake lights are on one wire which is akin to power.