so i was out side before and letting the truck idle after driving, and out of no where a strange high pitch noise came through the speakers. i looked down at the vlotage meter in the cluster and it was pulsating and seemed like it wanted to move down to 18v. i tuned everything on, lights running lights, hit the brakes, radio, defroster and hazards. nothing happend and it continued to make the noise for about 30 seconds after than stopped and voltage meter dropped down to 14 again!!!???!??!??! im so far confused and am getting sick of electrical problems! some one please help! thanks james

 

have you replaced the voltage regulator. i have never heard of one jumping around in voltage but who knows with the wonderful 1st gen. electrical system.

 

isnt the voltage regulator internal?

 

im pretty sure it is on the firewall. mine was anyways

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ok so i was looking around and from what i can find trucks pre 92 have external regulators either on the fender or firewall. 92 and up have the regulators built into the ECM.

 

i have a 1993 so its built in

 

lots of these trucks have grounding issues. a buddies truck was having issues like yours, we added an new ground to the rad support and that cured it. another issue that we found at the same time was that his battery had a film on it, and we were getting 8 volts from the battery case to ground , maybe that was screwing up the pcm . ithink the pcm regulates the alternator on the 93 . good luck

 

i re-did all the grounds and it helped but still having problems. what do you mean by film on the battery?

 

It was a greasy type of film like the batt had been overcharging you could actually run your finger across top and leave a mark in the dirt . disconnected batt and cleaned it usual way with baking soda and warm water.