Did you check voltage and ground at the fan wiring connector? Usually if you unplug the coolant temp sensor, the fan will run. If you turn on the ac, the fan run. You need to have wiring original for testing. Can you check for applicable mil codes? To check for codes, if your fully obd1 compliant, you use a jumper wire at the A & B terminals at the datalink connector. Turn key just till the dash lites come on, no further. The mil on the dash starts flashing, you count the flashes to get the codes. Your looking for two digit codes.