07-08-2012, 01:10 AM
Josh, I get what you are saying and in theory your thought process is correct. You probably do not need the red & black as you had suggested. The only thing I would say is it might be wise to check if your Cayenne has a Rear SAM (single activity module) that allows the brake lights & the trailer brake to operate, and if it does, the red & black wires might be for that very purpose.
mike
89 Carrera
#402
89 Carrera
#402