I have a 2012 F150 XL with integrated radio. I purchased a JVC Double Din on Crutchfield and it came with the wiring harness...Hooked up the wiring harness and triple checked all connections. All good right? Well I hooked it up to the harness on the truck and I get no power..Checked the head unit and its fine. Call Crutchfield and they tell me that I don't have a 12v power wire on my factory harness and that I should run a wire to my fuse box? My question is why is that if my factory radio comes on and works fine? Also am I missing something I need to get this to work?