my 90 xj battery gauge is in the red. the battery and alternator has checked out fine but the battery gauge has slowely just gone down all the way over the past 24 hours. the jeep starts up but the radio flashes on and off. anyone have any ideas.

 

Probably a bad chassis ground. Assuming battery voltage is correct measured at the battery and all your cables/connectors are clean and good.

 

Perform the procedure in Post #1 of my Tips in the link below before chasing your tail.

 

^^^ This!

The IP voltmeter on RENIX is a notorious liar, I don't pay attention to the scale behind it (just the grease pencil marks in front of mine.)

If you haven't verified system voltage independently, do so before doing anything else!

Having done that, if you're still seeing trouble, go through Cruiser54's bit next. Also, search for a writeup I've posted that will tell you how to test your primary electrical on pretty much any 12VDC vehicle system, and follow that. Amazing what you can learn from it...

 

This one, Jon?

https://www.cherokeeforum.com/f2/bat...or-test-78125/

 

Yah. I don't keep the link handy for two reasons:
1) I don't need it. I wrote the thing, I've been using it for 30-odd years.
2) Anyone who has ever sat at my feet to learn learned one thing first - I will not spoon-feed you. The most difficult thing to be done when learning from me is learning to think and do for yourself - I merely give you tools and hints. Some find it irritating. Many find it rewarding. '

Ask anyone who has learned from me - I'll push you harder in six months than you were in twelve years of primary school! But, you'll run rings around your contemporaries...

 

Yeah. If I've got someone learning face to face, I guess I can do that.

In this internet environment, different story.

 

Different styles, and I'm just cranky. Besides, I do prefer to stimulate our little grey friends...