Trying to hook portable sirius power supply to an upfitter switch. Found the upfitter wires, no problem. I took a cigarette lighter power supply and cut the end off. I took the negative to a grounded connection and then the #3 upfitter wire to the positive side of the plug. Nothing. I checked the upfitter wire for power and found it to work as expected with power only in the ON position and the upfitter switch on. I then tied the wires back together and am able to use the cigarette supply again but no power to the sirius dock via the upfitter. What gives? Really frustrating!