Overvoltage condition

Discussion in 'GM Electrical Tech' started by K0WJ, Mar 14, 2010.

  1. K0WJ

    K0WJ New Member

    There seems to be an overvoltage condition in my 2008 Silverado 2500HD Diesel. It has the dual batteries. I took it to the dealer I bought it from and was told there was nothing wrong, but frequently, I see over 16 volts at the power ports. This has already ruined one of my mobile radio transceivers and I either have to find a way to limit the charging system to less than 15 vdc or buy an expensive add-on voltage regulator like the ambulances and similar vehicles use.

    Does anyone know if the regulator can be adjusted to limit the voltage to 15 vdc or less?

  2. doug_scott

    doug_scott Rockstar

    Regulator is built into the alternator and is not working properly if you see 16 volts. Max should be 14.5 or so. 16 volts will kill the batteries as well.

    Take it back to the dealer and insist they come with you for a drive. Plug a volt meter in and show them the 16 volts. Mechanics cannot fix something they do not see. I ran into this with my G5, it was grinding between 2nd and 3rd when cold. Mechanic said nothing was wrong, so I left the car there overnight and took him out the next morning. I could get it to grind every time, they fixed it after that.

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