I have a 95 Cherokee Sport with the 4.0 I6. I purchased it about two months ago and have put about 2,000 miles on it already. Lately after I start her up, the voltage gauge will read +/-14 like usual, but while I've been driving, the gauge dips down to somewhere between 12/13 and stays there until I stop and restart the engine. I just replaced the starter about two weeks ago, and when I did that, replaced the battery, terminals, and most of the wiring coming off the battery terminals as it was all fairly corroded. At idle with a multi-meter I'm normally reading between 13.5/14 V, which is a bit low, but nowhere near as low as the gauge dips while I'm driving. (Also, I don't trust my $8 meter very much lol). With the ignition off, I read a full charge at about 12.5V. I can't really think of a way to test the voltage under driving conditions though. Should I just take the alternator off and go have it tested, or could it be something wrong with the gauge or instrument cluster itself? Thanks!

 

Take it to a local parts place you trust and ask them to test your charging system. It's free and most of the new testers they have now are pretty effective at diagnosing any problems. I'd maybe start there and maybe even take it to a couple places for a second opinion. Good Luck! let us know how it goes.

 

Do you know what your idle RPM has been lately? Is it at least 700+ RPM?

With lights off, your three biggest draws while driving will likely be your electric fan, your ac/heater blower fan, and your fuel pump. I'm wondering if you aren't seeing a drop due to low idle, or perhaps when your electric fan comes on. Then restarting has the electric fan off for a while, then back on.

Most, if not all, of these things can be checked without actually driving. And of course the RPM can be manipulated while you check things by reaching up and manipulating the throttle at the throttle body.

 

What you describe is perfectly normal.

Do nothing.

Factory gauges are ****.

 

Truth.