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Alternator / Power Problems

Discussion in 'Boss Plows Discussion' started by Sethro90, Jan 7, 2015.

  1. Sethro90

    Sethro90 Junior Member
    Messages: 13

    I have a 2001 Chevy 2500HD. It came equipped with the factory plow prep but I upgraded to a 200Amp alternator anyhow. I have recently put a 9'2" DXT on it. For some reason when you raise the plow or wing out, the truck looses a lot of voltage. Lights dim and sometimes the alternator will even squeal it pulls so hard. If you keep your foot on the gas it doesn't do it. I have replaced both battery's, alternator, tensioner, belt, and it has a new pcm in it. Any suggestions??? I have 2 other 2500HDs and I don't have the problems even if we switch the blades around.
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,390

    First I'd put a gauge in it and actually see the voltages. And maybe an amp meter
    Is the trk equipped with the a/c, just for grins turn off the defrost or floor settings on the blower.
  3. Sethro90

    Sethro90 Junior Member
    Messages: 13

    I clipped volt meter to it and at a normal charge it is around 14.5-15.? something in that range. When you raise or move the blade it will get under 12 like the 11.3 range and even to 9-10ish when it lets out the squeal.
  4. erebus

    erebus Junior Member
    from ny
    Messages: 16

    Is the higher output alternator pulley diameter smaller than the original alternators pulley? Sometimes they use a smaller pulley to increase the rpm of the alternator to make the 200 amps.
  5. Sethro90

    Sethro90 Junior Member
    Messages: 13

    It was the same size as the stock alternator.
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,390

    Well the voltage seems to be about right. Try the amps next.
    Only other things would be...Ck for how fast the voltage returns after the drain. Do a volt drop test at the alt, both batts, at both pins of the solenoid, and at the plow motor.
    How's the grounds as well?
    Might need to upgrade the alt output wire, and add a ground wire to the alt. Or what we call the big 3
  7. Sethro90

    Sethro90 Junior Member
    Messages: 13

    The charge wire has been upgraded as well as extra grounds have been put in from battery to frame, engine to frame, engine to body and body to frame.
  8. haejinjoe

    haejinjoe Junior Member
    Messages: 28

    You mention that it has a new belt and tensioner. Is the new belt slightly longer than the original? If the tensioner is at the end or close the the end of its travel due to a belt that is too long, it will not maintain enough tension on the belt allowing it to squeal at times.
    I have an 04 which has always done the voltage gage movement that is described in this thread, but it has never squealed. Has original belt and alt with 111K. Good luck with finding the source of the trouble!