1989 Oldsmobile Ciera Cooling Fan

The radiator fan should come on if coolant temp exceeds 223 degrees F. It should run if you turn on the ac. Usually if unplug the coolant temp sensor, the fan will run. If you check for mil codes using a jumper at the aldl, the fan will run. Any applicable mil codes?

the fan is not coming on after 20 minutes of driving at highway speeds. no mil codes, no check engine light, temp gauge does not work. i'm thinking the fan maybe be toast or there is a short somewhere. checked fuses and applicable ones seem to be fine.

You can take the electrical connector loose from the fan, use jumper wires from connector to battery for voltage and ground, to see if the fan will run. Use an inline fuse on the jumper, just in case. The yellow wire is voltage, black is ground. If the fan won't run, suspect the fan motor.

it appears that the fan is cycling properly. I just hadn't waited long enough to notice. the car was still overheating so I tried a new radiator cap and that seems to be working. thanks for your help