As the title states this concerns a 90 pickup with the 22r. While driving in any condition the lights will begin to flicker (significantly dim) and after a short period of the electricity loss the engine will begin overheating rapidly. This will occur fairly frequently but it usually regains voltage and cooling after a few seconds, not overheating completely (yet).

I had the belt which drives the fan and the alternator replaced thinking it was slipping but it did no good. A mechanic did mention the fan clutch is pretty much shot, could that be my problem? Would that cause the alternator not to deliver power as well?

Thanks for reading and I would really appreciate any advice.

 

Though the fan and alternator are driven by the same belt, both problems being caused by a faulty clutch is not likely.

More likely is the regulator or alternator is having issues... maybe a loose connection at the alternator, causing the battery to not charge. The resulting drop in voltage can cause the temperature gauge to read inaccurately since its operation is based on voltage.

 

Very helpful, I will check the connections at the alternator first thing tomorrow. What should I look for while troubleshooting the regulator?

 

My first guess would be the gauge cluster is shorting or something. It could also be some kind of grounding issue. I had an S10 Blazer with bad gauges. Turning on the headlights would make them worse. It turned out to just be the ground.

Get some kind of volt meter. When the charge light starts flickering check the actual voltage with the gauge and see if it fluctuates or drops. If the voltage is steady and appears to be ok, then it is probably an instrument cluster or wiring problem. Getting a seperate temperature gauge is also a good idea, but would be more expensive and a little more work than testing the volts.

The fan clutch should not affect the alternator. You can take the alternator to most auto parts stores and they will test it for free. Their machines are more specific than just a voltage gauge. I have always taken alternators out of vehicles to be tested, but I have seen portable testers wheeled out to peoples cars. I would assume they can test alternators without removing them from the vehicle.