Hey guys, I need your help diagnosing whats causing my voltage to be so high. Got the car back from the shop for a coolant flush and a suspension fix (replace centerlink, idler arm) and now for some reason my cars voltage is at around 18 volts when cruising. Whenever I am stopped at idle at a light it drops to 13-14v. I used my DMM and measured the output at the alternator and its pushing 18 volts. I don't wanna burn anything up here. I think something is up with the alternator. But that would make me mad because I just replaced it not 3 months ago. Could the belt possibly be to tight? Remember this all started happening after the car was in the shop. Thanks alot!

 

your alternator is bad.
it was just coincidence that it went out when it did.
i would replace it now, it can burn out pretty much everything electrical on your car at 18 volts.

 

Thanks! I replaced the alternator and everything is back down to 13-14v. Thanks alot! The guys at AutoZone were convinced it wasn't my alternator and that I had a much more severe electrical problem with my car. The alternator passed there stupid machines test 3 times. But I told them I wasnt worried how many amps the alternator was putting out. Morons. They gave me a new alternator and told me it wasn't going to fix the problem. Lol, the people they hire there seriously need to have an education before they apply...

 

no problem

over charging can only come from the alternator, someday maybe the people at autozone will learn that.

.