I have a 2012 Subaru Forester toad. Just hooked up BLUE OX LED towing lights in the existing tail light housing. The wiring runs thru the car interior and is connected to a 4 prong socket at the front of the car. I made up my own 4 wire connector harness to go from the motor home to the car. To tested the lights, I hooked up a 12 volt battery to the motor home end of the harness and the towing lights worked (parking and turn/brake). When I hook up the motor home to the car, the turn/brake lights work but not the parking lights. The parking lights will not work when hooked up to the motor home, just a separate 12 volt battery. Yes, I have power (parking lights/brown wire) at the car end of the wire harness when hooked up to the motor home! When connecting the harness to the car or motor home (with the motor home parking lights on) the car parking lights will momentary flash on, but not stay on. I also checked continuity of the harness with a ohm meter. Every thing should work. I even stuck pins in the wires to check the voltage. This is impossible, it will work off a separate 12 volt battery but, not the motor home. Has anybody else had an issue like this?