So I have a voltage gauge in my Jeep on my A-pillar and it used to work perfectly fine.. When I'd turn the key to accessory, it would read about 12 and when I'd turn the Jeep on, it'd be between 13 and 14. Well recently my gauge has been going crazy.. The little orange stick just goes back and forth really fast when I turn the Jeep on and never settles anywhere. What the hell is the problem?? I've retraced all my wires and everything seems to be ok?

Thanks guys

 

Where did you tap to get the voltage reading?
Have you recently changed the location?
Have you recently added an electrical device?

Connect an analog volt meter directly to the battery and see what it does, with the engine off, then on.

 

Like the post above said, I'd measure the voltage with a volt meter to isolate the issue. If that checks out fine, then I'd guess the gauge needs to be replaced.