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What is "normal" voltage drop when turning on heater fan? Mine drops from about 14.5 volts to 13.5 when running fan on high speed. If this is more than normal drop, should I replace the fan motor, or can it be lubed?
No , they cant be oiled . Very few electric motors of any kind can be oiled today , everything has sealed bearings . The resistor for the fan motor allows the motor to operate on 12 volts when on the high setting is why you notice the decrease in voltage . Just out of curiostiy , What model yr is your truck ?
You mentioned the electrical . I had to replace the alternator in my truck a few weeks back & found out that there have been some problems , & I only think this applied to the 1990 model yr , with the rectifier plug on the alt . Apparently the pins over time work loose & they create some heat with the potential for fire & or melted wires . My plug showed some initial signs of being warmer than normal so I replaced the plug . A buddy of mine owns an automotive electrical shop , He told me about the problem. Hes replaced several of these plugs .
The alternator I purchased last year also had a plug, short pigtails to connect to existing wiring (with butt connectors) and some contact lubricant. They recommended replacing the plug with the alternator for the same reason, some sort of problem with heat buildup in the plug and resulting alternator fire. I replaced mine also, sounds like the kind of problem you don't want to have.....
I experienced the alternator fire....When you replace the alt., change the plug and don't pull it once it has been plugged in... I was lucky enough that the damage was contained to the alternator.
From What I gathered its a fairly common problem . I didnt realize it extended to more model yrs than just the 1990 models . It was a simple replacement ... So I guess if anyone reading this experiences the same type of trouble , replacing the rectifier plug along with a new alternator would be cheap insurance .
If you are careful, you can drill a SMALL hole in the back end
of the shaft. Use light oil (like 3 in 1) then seal hole with
RTV. Will do for awhile and save replacing it.