i have a 1997 f150 4.2 liter. and one day the heater kept running afteri shut it off unless i put the heater into the off position, now it tries to start when the truck is running.
Blower motor is run threw a blower motor resistor that can cause this, may be bad.
I meant the truck tries to start
If you mean the starter engages after the engine is running, then power is being supplied to the solenoid when it should not. Begin by checking the relay, then backward.
Looking for a Used F-150 in your area?
CarGurus has 182,703 nationwide F-150 listings starting at $1,500.
Search Ford F-150 Questions
Ford F-150 Experts
Related Models For Sale
Used Cars For Sale