Years ago I took my fisher minute mount ez-v off my 05 2500 Silverado and put it on my 09 2500 GMC. When I did this the dealer said all I needed to do was to change the connecter that plugs into the back of the head lights, and sold me the new connector. It took me a few years to get around to changing this because it is not easy to get to the back side of the headlights on the GMC, and I usually only use it to plow my own driveway. So last year I finally did and doing what they recommended, I have no high beams on the plow because the 05 Chevy had hi/lo in the same bulb and the 09 GMC has separate bulbs. My plow has 3 plugs and I have a 4 port isolation module. What do I need to do to get the lights on my plow/truck working properly? Is there a headlight harness that I can purchase and does anyone know the part number?