I have a Curt 56045 wiring harness that was 80% installed and never used. I realized later that I needed the 7 pin and had to go with the Volvo OEM towing module and cable. The Curt basically taps in where the rear lights connect to the wiring harness. So it's 100% non invasive and reversible. Not pictured, but included, are the zipties and fuses to complete a tidy installation.

$20 local, $30 shipped paypal or Venmo accepted.

I also have a Draw-tite hitch, the 5,000lbs version. This is Brand new in box. I bought it, but then Draw-tite ended up warrantying my messed up hitch. I just waited too long and I'm outside the return window. Box is a little trashed so shipping is probably not possible. Amazon says they're going for $280-310 new, but I'm pretty sure I paid $200, so $160 local. If you buy the hitch, I'll toss in the wiring, as long as someone else hasn't taken it first.

I'm in central NJ but willing to travel a bit to meet up if needed.