[073]

Heres the problem my truck 80 F-150 4x4 351M backfires when I turn the heater fan switch on, the switch only works on high. Today when I turned the heater on it killed the engine and the ignition switch was dead until I turned it off and back on again.

I checked the grounds and they were alright, checked the coil and it was losing a volt or so when I turn on the heater switch.

I have replaced the ignition switch, cap and rotor since this started.........

Any ideas??????????

Thanks

 

[953]

the blower motor.
first, if it only works on high, the resistor inside it is probably shot, as the high mode bypassed the resistor.

 

[073]

On the way to city this morning it died completely and left me stranded. After getting a new blower motor and blower motor resistor installed I still didn't have anything. So after checking everything I could think of I found that I had burned a wire leading to my amp gauge. So I disconnected the amp gauge and ran power wire back to solenoid and the truck started up fine. Had all speeds with the fan and didn't seem to have any other problems. Lets us hope, the morning will tell.

Thanks Burned for your input.