A few days back my heater fan control and windows ceased to function. I discovered that the blower motor is functional and disconnected it from the factory wiring and hard wired it to a toggle switch so I at least have high fan now. I believe the resistor for the blower is bad. Can somebody tell me where to locate the resistor on the truck and maybe where I can purchase a new one? Napa and O'Reilly's both say they are no longer manufactured. My windows stopped working at the same time as the fan control. Coincidence? or somehow related? I'm not really accomplished in the electrical department. Thanks in advance for any good information...

 

I thought they shared the same fuse but the don't. They DO share the same terminal on the ignition switch on my 89. They have a separate fuse for each one though. I would suspect the ignition switch is bad. Do you have a tilt wheel? What year is your truck?

 

This may or may not be your situation.

On several of these vintage trucks, both the heater-fan and power-window circuits will be all burnt and melted at the fuse-block --- which is a complete joke(the fuse block).

On all of these that I have encountered, I have removed those two circuits completely from the fuse-block and hard-wired them through good heavy fuses.
Thus, the factory switches and resistor still functions as normal; with a big added bonus, the windows work when the key-switch is OFF and the key is nowhere around.