Ok new member although I have read more posts than I can count before joining. A few weeks ago my 97 SE started having the "check gauges" light illuminate in all its bjg scary redness and the voltage gauge would bottom out to nothing. Soon after, probably within a mile it would pop back up and go away. Then it did it again but didnt go away so I parked it and assuming it was the alternator took the alternator to get tested...but it tested fine. So then I thought ok maybe its the voltage regulator in the ECU and I wired in an external voltage regulator to bypass it from a late 80s dodge(brand new but for those) then it proceeded to jump between about 13.7 volts at normal to 19 volts sporadically while driving. What the heck is going on with this poor thing? I have again removed the alternator and battery and am getting them both tested today at at least 2 locations for each. If they are both good im not sure what I should do next.
97 2.5 voltage all over the place
- Thread starter TLeadabrand
- Start date
The first thing that came to my mind though was the voltage regulator built into the PCM.
If it's not that, I suspect it's a wiring issue, so inspect the wiring thoroughly and check your terminals!
If it's not that, I suspect it's a wiring issue, so inspect the wiring thoroughly and check your terminals!
Whenever my volt meter would peg at 19, it was the cause of dirty/corroded terminals. It pegged again one day and I did my usual clean, but that didnt help. I took a look at my battery terminals and found a hairline crack in each, which wouldnt allow the terminals to be snug against the battery posts. New terminals solved that issue. The one time my volt meter dropped, I had a loud squealing sound. I had just swapped belts and I the one I bought was about an inch to long. I believe it wasnt enough tension to turn the alternator and the belt was slipping on its pulley. Swapped in a much shorter belt with greater tension and havent had an issue since.
Afternoon update. Well the alternator came back as good and the battery is toast. An hour and a half on the charger and it got super hot and only 6 volts. Just need to determine if it was cause of problems or victim of the problem. Im thinking victim because it was running on battey only when it was first doing the voltage dropping. Then the whole lot of 19v overcharging finished it off. Will get new battery this weekend.
Update. I cleaned every ground in the engines general vicinity I could find then reinstalled my alternator minus the external relay and installed the new battery. I bought a new battery on the cheap from Autozone incase it eats another one. I started it right up and let it run for awhile including revving it up and re parking it. No issues whatsoever. The gauge stays right at 14 and only slightly dips for a half second if I kick the lights and heater to max at once otherwise no vlotage drops or overages and no gauge illuminations. My multimeter confirms that it is right at 14.02 while running. Must have been a bad battery or ground or both?
Ok another update....sigh.... New battery, check. Alternator checked out great at several stores, check. Jeep ran great for a few days. Boom back to voltage gauge bottoming out. I reinstalled the external regulator. That worked for a day. Now its not charging at all. Back to square one.. Im out of ideas...
97TJGWB
New Member
Did you ever come up with a solution to this? I've been having the same problems as far as the voltage jumping to 18+ then dipping to bottom of the gauge.