To get you started, look at the ignition switch. They can develop burned contacts, especially if you use the heater fan on the highest speeds a lot. Also look for two blackened terminals in the connector and signs of melting on the plastic connector body.
If everything looks good at the connector, use a test light to find the two or three 12 volt feed wires, then turn the switch to "run" and look for the additional wires that get 12 volts. I don't have a service manual for that year, but you'll be looking for a pretty fat wire that doesn't get 12 volts or the test light just lights up dimly. If you find one like that you can use a stretched out cotter pin to jump 12 volts to it to see if the fan runs. If that works, suspect the switch.
Monday, April 22nd, 2019 AT 6:14 PM
(Merged)