2001 Ford Expedition owner here. I've noticed that sometimes when stopped in idle, with my A/C on, the RPM gauge fluctuates along with the power/lights for everything else in the system. Note that this doesn't always happen when my A/C is on. Very much so an intermittent issue.
I hooked my DMM up to the battery, cranked the engine and turned everything on. Headlights, Max A/C, radio, etc. It's reading around 13.6. After that, I pressed down on a couple of power window buttons, and as soon as I did, the voltage dropped even more to about 13.1 volts.
So I can confirm that it's on it's way out. I have a new alternator, however I wonder if I should wait a while before I swap it since it doesn't seem severe?
I hooked my DMM up to the battery, cranked the engine and turned everything on. Headlights, Max A/C, radio, etc. It's reading around 13.6. After that, I pressed down on a couple of power window buttons, and as soon as I did, the voltage dropped even more to about 13.1 volts.
So I can confirm that it's on it's way out. I have a new alternator, however I wonder if I should wait a while before I swap it since it doesn't seem severe?