High Voltage Reading on Dash Guage

wildwood1

Have a 2001 Yukon XL. Couple of months ago, voltage meter started bouncing between 12 and 14 volts when sitting idle. Original alternator in vehicle, so it was replaced. After a couple of months of replacing alternator, the battery symbol light up on message center and dash volt meter was ramping from 14 volts to 17-18 volts. Cut car off and restarted. Problem went away for a while. Started happening more frequent and thought there was a bad voltage regulator in the new alternator. So replaced alternator again. Couple of months later, high voltage reading starts up again. What is causing this high voltage to occur?

jpp75

Might be a voltage regulator. We had one go bad in a Lincoln a while back but it was built into the alternator so it required an alternator replacement. I think on most other cars the voltage regulator is a separate component.

Mr_Shiftright

The regulators are built in on this truck, and the alternator is not repairable/serviceable. It might be interesting to test the alternator output with a VOM meter while this spiking is going on.

jpp75

Mr_Shiftright said:

The regulators are built in on this truck, and the alternator is not repairable/serviceable. It might be interesting to test the alternator output with a VOM meter while this spiking is going on.

Thanks Mr Shiftright. My next guess was a sending unit, but your test would confirm if that's the issue.