Going to install a 'backup sensor' on mother's 'friend's' car--popped the liner from the trunk lid to look at the reverse light wiring. The aftermarket sensor needs to tap into the reverse light wire and associated ground. The 3-wire plug that goes into the bulb assembly has 2 black with red dash wires, and a solid black wire which should be the ground. Question is, not sure which one of the wires going into the plug is the hot wire to the reverse bulb since its the same color/pattern as the wire going to the rear fog light (I can't for the life of me find my test lamp....). So question for the collective is if anyone knows the wiring order on the plug? Many thanks!