First off, take a voltmeter (a digital; even a Harbor Freight one!) and see what voltage you're getting when the gauge is maxed out.

The regulator is in the ECU, so hopefully it's more a bad meter than the system running too high; but if it is, you can use an external regulator on your alternator and get the voltage right.

RwP

 

 

I have a statement and a question.
I had an overcharge indicated on my dash. I was directed I forget by whom to getting my battery checked. I replaced it and the charging went back to half or less.

If I were to have this issue again where would I test with my Harbor Freight voltmeter?

 

First is at the battery; second is at almost any 12V tap (I have a voltmeter that plugs into the cig lighter and gives me two USB ports also, plus a pair of pass-through aux sockets not rated for a cig lighter but great for a secondary device like my radar detector).

RwP

 

yeah when batteries die these trucks can do all sorts of crazy things..... when the one in my Wrangler died the charge gauge pegged...... soon as I replaced the battery it went back to normal/
also between my 92 and my 96 Dakotas that are functioning fine the needle stays closer to 1/2 gauge on the 96 and normal running on the 92 is about 3/4 scale and has been in the whole 40k miles I have owned it.

 

Ralph, I have one of those cig lighter voltage gauges too, very useful, it has the USB outlet as well. A couple of times the readout has started to flash on mine, I haven't caught the exact voltage at which it begins to flash, but its around 14.8V. Think it might be trying to indicate an over-voltage condition, but at less than 15V it seems a little overly sensitive to me. Anyway, if I turn the headlights on it drops the voltage and the display stops flashing.

Anyway, it has come in very handy as a troubleshooting device. My wife's Kia was having a starting issue a while back, wherein it would start right after being driven but wouldn't if I came back a couple hours later. I'd have to charge the battery to get it to start again. I thought maybe I had a draining issue, until I plugged the cig lighter gauge in. I noticed the battery voltage began dropping right away; slow enough that it would start if tried again soon, but in as little as 6-7 minutes it would show weakness. Even headlights shouldn't drag a 2 year old battery down that fast, so I had the battery checked - it was faulty. That gauge also lets me know when its time to put a trickle charge on my garage queen Dakota. She don't get driven much in the winter.