khutchinson22

I got a red battery warning while driving today so I hooked up the voltage meter and it was sitting at 12V. Had my wife get in and rev the engine a bit and then the voltage jumped to 14+V (normal range). I let it sit a bit while running and then revved it up again. This time the instrument cluster blacked out, it wont shift out of park and I'm getting over 18V readout. The battery is only 18 months old and I replaced the alternator less than 6 months ago. I'm thinking it could be a bad alternator/voltage regulator but I'm looking for other possibilities that I can test.

khutchinson22

^^^

khutchinson22

Just checked the voltage at the battery again and its dropped below 6V. Something is draining the battery as it sits.

Dr Matt

Sounds like a bad regulator to me as well, but could be more. Do you have an actual charging system analyzer or one you can borrow? Must be a big drain if the battery was OK and now it is that low from sitting for just a day.

khutchinson22

The part that threw me was the super high voltage reading I got before the system went blank. Could a voltage regulator malfunction produce high voltage readings? I'm in the process of pulling the VR right now and getting it swapped out by Auto Zone. Will report back when done there. Hopefully that's all it is.

Dr Matt

Yes, a bad VR is the only reason you would overcharge like that.

khutchinson22

SOLVED!

It turned out to be the Voltage Regulator.

All is well again.

biker349

do you have the water cooled alternator? what year is it? if it's 2003 or newer i believe the voltage regulator is very pricey. if 2002 or older it's pretty reasonable. if it's 2003 or newer i was wondering what you paid for it and where you got it.
thanks

khutchinson22

2004. Not water cooled. I had just replaced the complete alternator about 6 months ago and it still had a warranty. The parts store was kind enough to let me just swap out the bad voltage regulator with one from another new alternator (after bench testing, of course). The alternator, if I remember correctly, was about $160 w/ core.