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1 wire alternator

Discussion in 'Chevy Trucks' started by 81c1500, Feb 2, 2004.

  1. 81c1500

    81c1500 Junior Member
    Messages: 29

    I have written in the past and the knowledge received is very helpful and appreciated. My new problem is with the alternator. I recently installed a voltmeter in the dash and noticed during driving the voltage would start about 14v then climb to 18+v at about highway speeds. I installed a new voltage regulator that kept the voltage no higher than 16v, but 2 days after installing the regulator the voltage climbed back up to 18v. I broke down and bought a remanufactured alternator from Advance Auto Parts and the alternator ran at 18v. The reason I came upon this problem is the new battery I bought was bubbling acid from the seam. I figured I am overcharging the battery. Any other help would be appreciated. Thanks
  2. towman

    towman Member
    Messages: 39

    ok i am assuming your truck is a 81 gmc, you alternator has an internal regulator , if that tests out good you need to check to see what the voltage is at the red wire on the plastic plug that goes into your alt, with the truck not running the voltage should be the same there as it is at the bolt on wire on the back of the alt, if not the same will make alt over charge, if they are differant you can cut the red wire and not use it in the plug and connect it to the wire on the back of the alt, that is easier than tracing down a wiring problemn, if you have any questions feel free to ask