Jeep Gladiator electrical gremlins

[mtudb24]

Long story short. Bought a new gladiator in Oct 2020 as a 2021 model year. Oct 2024 my "avenger" light came on. In November, the truck died in my driveway at 8V and I bypassed the aux battery by pulling the negative battery cable and fuse 42. Was happy to get 4+ years out of aux battery.

All's well. Then in Jan 2025, my voltage gauge on my cluster went to 16V and all lights on the cluster came on. Traction control, service stability, park brake, abs etc. My main battery was shot. Replaced with a new group 94 battery.

Fast forward to now at 7 months later. I get the same messages on my cluster of traction control / brake system / abs after driving for a bit. Voltage at idle drops to 11 plus and while running goes over 15.3V.

I pulled my battery and used a AGM battery charger and it was 77%. Took about 1.5 hours and it was at 100%. Started driving home from the cottage tonight and about a hour into the drive, the same thing happened. Traction control / service ABS lights came one when my charging voltage on my cluster went to 15.3+Volts.
Got home and put a volt meter on the battery with the cables connected and disconnected and it was 12.7V but my cluster showed 10.9V. Truck wouldn't remote start ( pushed the remote start button and it would beep once but wouldn't start), but started right up when using the push button.

Why in the world would my battery show 12.7+ volts with and without the battery cables connected but my dash voltage would show 10.9Volts?

Gonna take the battery to the shop I bought it from for a load test but I can't imagine its bad if it shows 12.7V.

Could this be a bad IBS sensor or bad alternator or ????

Thanks for any advice.
Todd

 

[cozdude]

Long story short. Bought a new gladiator in Oct 2020 as a 2021 model year. Oct 2024 my "avenger" light came on. In November, the truck died in my driveway at 8V and I bypassed the aux battery by pulling the negative battery cable and fuse 42. Was happy to get 4+ years out of aux battery.

All's well. Then in Jan 2025, my voltage gauge on my cluster went to 16V and all lights on the cluster came on. Traction control, service stability, park brake, abs etc. My main battery was shot. Replaced with a new group 94 battery.

Fast forward to now at 7 months later. I get the same messages on my cluster of traction control / brake system / abs after driving for a bit. Voltage at idle drops to 11 plus and while running goes over 15.3V.

I pulled my battery and used a AGM battery charger and it was 77%. Took about 1.5 hours and it was at 100%. Started driving home from the cottage tonight and about a hour into the drive, the same thing happened. Traction control / service ABS lights came one when my charging voltage on my cluster went to 15.3+Volts.
Got home and put a volt meter on the battery with the cables connected and disconnected and it was 12.7V but my cluster showed 10.9V. Truck wouldn't remote start ( pushed the remote start button and it would beep once but wouldn't start), but started right up when using the push button.

Why in the world would my battery show 12.7+ volts with and without the battery cables connected but my dash voltage would show 10.9Volts?

Gonna take the battery to the shop I bought it from for a load test but I can't imagine its bad if it shows 12.7V.

Could this be a bad IBS sensor or bad alternator or ????

Thanks for any advice.
Todd

A bad cell within the battery will show good voltage when it’s stable and be all over the place when it’s running.

 

[bobfriesenhahn]

Long story short. Bought a new gladiator in Oct 2020 as a 2021 model year. Oct 2024 my "avenger" light came on. In November, the truck died in my driveway at 8V and I bypassed the aux battery by pulling the negative battery cable and fuse 42. Was happy to get 4+ years out of aux battery.

All's well. Then in Jan 2025, my voltage gauge on my cluster went to 16V and all lights on the cluster came on. Traction control, service stability, park brake, abs etc. My main battery was shot. Replaced with a new group 94 battery.

Fast forward to now at 7 months later. I get the same messages on my cluster of traction control / brake system / abs after driving for a bit. Voltage at idle drops to 11 plus and while running goes over 15.3V.

I pulled my battery and used a AGM battery charger and it was 77%. Took about 1.5 hours and it was at 100%. Started driving home from the cottage tonight and about a hour into the drive, the same thing happened. Traction control / service ABS lights came one when my charging voltage on my cluster went to 15.3+Volts.
Got home and put a volt meter on the battery with the cables connected and disconnected and it was 12.7V but my cluster showed 10.9V. Truck wouldn't remote start ( pushed the remote start button and it would beep once but wouldn't start), but started right up when using the push button.

Why in the world would my battery show 12.7+ volts with and without the battery cables connected but my dash voltage would show 10.9Volts?

Gonna take the battery to the shop I bought it from for a load test but I can't imagine its bad if it shows 12.7V.

Could this be a bad IBS sensor or bad alternator or ????

Thanks for any advice.
Todd

In addition to what cozdude says, keep in mind that battery testers in the store primarily test discharge rates under load similar to starting. They may not detect issues which occur during normal operation.