I decided to take out the heater box. Being I don't have a heater or an air conditioner on this truck and the box was blocking the left bank of spark plugs I figured it would make it easier to do a tune up which is what I am about to do. After I got it out, I tried to start it but nothing. I checked and my plugs and no spark. I didn't think there should be any wiring going to my heater that should effect my engine starting or is there a ground I might have disconnected?