<strong>Yahoo Message Number: 19133</strong>Mike: I have a similar unit, Honda Pilot. It has the factory trailer wiring harness in the storage compartment in the rear. Hopefully your MDX has the similar wiring. <br/>I spliced into the factory wiring harness and ran the wires along under the car and up to the firewall where I installed the diodes and labeled them. It makes it simple to check...