I have a 99 xj with 136k. The check gages light came on and the voltage meter was pegged to the left. (Saying it wasn’t getting any) I could turn it off and back on and then it would be reading 12v for a little while. Just recently it sputter and then died. I took the alternator to get checked and he said it was good. Replaced the battery and it drive fine for an hour then the check gages light came on and the voltage meter was pegged dead again. I read something about a voltage meter externally? I’m not even sure where to go from here! Any help would be much appreciated!

 

I'd lean towards bad connections or bad ground somewhere. I'm sure someone will chime in with a good list of grounding points to clean..... I dont know them like some people...

 

Agree, with RockyMtn96XJ. Refresh your grounds, don't just look at them.........remove them, clean them and then tighten them back down. You could also check the wiring as it runs from the alternator to the battery.

Sounds like its time for you to get a reliable multi meter, you can check your battery's standing voltage while vehicle is off, start it and you can see the strength of the battery by how far the voltage drops and then check its charge rate once the engine is running.

 

 

You need a meter to figure out what's going on. Measure the battery voltage when it's running. Check if you have 12-volts to the alternator coil, and if the engine computer is providing the ground to the other side of the coil. In otther words, is the alternator being told to charge and it isn't, or is it not being told to charge.

 

thank you!! I check all the grounds and then checked the voltage with a meter. When I started it the voltage dropped to 12.2. Got a new alternator and it’s running fine now. Must of just been an unlucky time to test it? I appreciate you guys!!

 

Congrats!
Got to smile at a happy result!

 

Who checked the alternator? Autozone seems to be the worse for testing, often claiming they're good when they're not.