Yes, but 2 wires are to drive left and right relays and 2 are for the power to the contacts of those relays. The parking lights are good to go. The gm hitch comes with harness that has the relays. Relays get tied above the hitch. I have pin numbers if needed.
I'm still trying to find a signal that the car is turned on in the rear area to drive a relay for sending battery voltage to a 7pin. Don't want to drain car battery when parked.