I recently installed a new Kenwood headunit into my 1988 GMC Pickup. Made sure all the wires where matched to the correct colors. The stereo doesnt work neither does the HVAC. The underdash lights dont work (my dome light never worked in the first place). The headlights still work. The truck still starts. Everything works except the stereo and the HVAC. When the truck is off the stereo will work but when you turn the volume past 30 or open the door (interior light comes on) the radio will turn off. Also when the truck is running the radio cuts off. I checked the CTSY 20A fuse and it doesnt seem to be blown. Any suggestions?