After parking on a 96 degree afternoon for five minutes the engine would not restart. I could not hear the fuel pump. After towing it home I sprayed starting fluid in the intake and it started momentarily. All fuses are good. Applied 12v to the fuel pump test terminal but pump failed to start. Applied 12v directly to the fuel pump which began working. Engine started normally. Swapped the pump relay with the horn relay, reconnected the pump cable and engine would not start. Horn works with either relay. The pump cable will not light my test light. Why is power not reaching the pump? ECM? VATS?