We have a 1998 Jeep Cherokee. The voltmeter drops to 9 when we drive the jeep. By stopping, turning off the car then starting it up again, the voltmeter returns to between 12 and 14. It may or may not happen again while driving. The problem is intermitent, but seems to be happening more often. What's the problem?

 

checked your fuses? Check pinched wires under the battery tray

 

How is your belt tension?

 

How old is your battery? How long since you cleaned your cables?
And Welcome to CF.

 

Welcome to CF.

Hey Blue, do those 98s still have the voltage regulator in the alternator, or does the ECM regulate voltage?

 

how about a crappy stock guage............i would only trust it backed by a voltmeter.....otherwise...ur guessing.

 

clean your battery posts off

 

I think the computer handles it but I'm not positive.

 

Sounds like alternator is going bad

 

That is what I was thinking. Makes this a little more of a conundrum.

 

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what wiring diagram is it under? ill get it

 

The pcm handles the charging of the battery and monitors battery temp,there is a sensor located next to the battery tray. the evr located in the pcm also monitors line voltage,if the evr goes bad you have to replace the pcm to fix charging problem.
Next time this happens check voltage at battery with dvom and compare,it may just be a bad guage.
If I remember right chrysler switched to the pcm for voltage control in 91 when they switched to the chrysler control system and away from the renix.

 

What I think we need is the ECM for the 98 with 4.0L. It is in my Chiltons, but I don't know where it is right now. Buried somewhere in the shop.

 

i got a secret for you....online

go to http://www.powerlibrary.net/Remote/R...?ID=Kaltreider

24002000255222
then

- Auto Repair Reference Center

then again

Auto Repair Reference Center


wallah online everything!!!!!!!!

 

OK Joanne, I think I have an answer for you. It looks like according to my wiring diagram that the ECM, or computer if you prefer, controls the voltage on the alternator via a black and green wire. I would suggest that you take that plug off and clean the contact areas up with some electrical cleaner and then put it back. If that doesn't fix it, you may have a problem with the computer. The only way to fix those is to replace them.