alternator high voltage

89supracrazy

New Member
Oct 31, 2009
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It was my alternator. The voltage regulator was bad. If you have a meter that has a diode check on it you can put one lead on the main positive stud and the other on the frame of the alternator and see if it reads both ways when you swap your leads. It should only read one way. I tested my bad one and the good one. The bad alternator showed readings both directions on my meter. While the good alternator only read in one direction. Make sure when you do this that you disconnect all wiring to the alternator. Also read the voltage at the battery when it is running and rev it up at the throttle body. It will show normally at idle but when you rev it the voltage will start to climb. It should never go over 15 volts. Mine was hitting around 17.5 volts. Hope this helps.