Jeep Gladiator electrical gremlins

mtudb24

mtudb24

Caught the Bug
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
 

Attachments

  • Battery voltage battery cables connectred.jpg
    Battery voltage battery cables connectred.jpg
    156.1 KB · Views: 5
  • Battery voltage battery cables disconnected.jpg
    Battery voltage battery cables disconnected.jpg
    159.3 KB · Views: 6
  • Battery volttage at cluster.jpg
    Battery volttage at cluster.jpg
    140 KB · Views: 5
  • Dash LIghts after hitting 15.3V.jpg
    Dash LIghts after hitting 15.3V.jpg
    160.7 KB · Views: 5
mtudb24 said:
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
Click to expand...
A bad cell within the battery will show good voltage when it’s stable and be all over the place when it’s running.
 
mtudb24 said:
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
Click to expand...
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.
 
HighwayTrout said:
Have you tried a new battery(ies) yet?
Click to expand...
Yes, put a new Group 94 battery about 6 months ago. I "isolated" and took the aux battery out of the equation by removing the negative cable and pulling fuse 42. Gonna try and get the new main battery load tested tomorrow to see if that's the issue.
 
All grounds checked. Battery passed the load test but when we put the alternator test tool on the truck, the tester kept saying the voltage regulator failed.

I'm wonder if this is actually a alternator issue? I know the PCM / BCM / IBS control all that voltage stuff.
 
I Honestly quit. Time to start a new project.

Went out to the truck today, remote start worked, blower motor worked, headlights didn't flicker and the voltage never fell under 13.2V at idle to 14.2/3 while at 1000rpm or at 3000rpm and no warning lights on the dash. Its like nothing ever happened. WTF???? If your broke, stay broke so I can fix you vs trying to chase a Ghost.

For you Seinfeld fans, I'm just gonna drive it about 35 mins south to 8 mile and leave the keys in and walk away, so have at it!!!! At least you won't have the "Beast" smell to deal with 😎 :) 😎 :)
 
Last edited by a moderator:
mtudb24 said:
I Honestly quit. Time to start a new project.

Went out to the truck today, remote start worked, blower motor worked, headlights didn't flicker and the voltage never fell under 13.2V at idle to 14.2/3 while at 1000rpm or at 3000rpm and no warning lights on the dash. Its like nothing ever happened. WTF???? If your broke, stay broke so I can fix you vs trying to chase a Ghost.

For you Seinfeld fans, I'm just gonna drive it about 35 mins south to 8 mile and leave the keys in and walk away, so have at it!!!! At least you won't have the "Beast" smell to deal with 😎 :) 😎 :)
Click to expand...
Might wanna remove that link…
 
Last edited by a moderator:
Sharkey said:
You are missing the obvious point related to the aux battery removal. There is a reason why it’s there in the first place.
Click to expand...
Not trying to be a smart ass, but I would love to hear the technical reasons why the aux battery needs to be in the equation? Not just because its there from the factory or that's what my buddy from Stellantis said, but electrical / architecture / schematic reasons why it needs to be there, and I am all ears. I am a vehicle wiring engineer by trade for 30+ years for the Big 3. So I would love to understand why.

I have to believe there is a reason why 1000's and 1000's of Jeep JL and JT owners have disconnected the aux battery when it fails and all the reasons why JSCAN / Tazer / and other companies make tools to disable the start stop system and remove the aux battery from the equation who have no issues afterwards. I haven't counted the number of YouTube videos showing how to disable the aux battery and start stop function with no long term issues.

Why after 9 months of disabling the aux battery would the truck have issues? And then 2 days later and ever since, the truck has been fine?

My vote is something related to a possible IBS sensor fault / failure that "reset" itself after being disconnected from the main battery for a set amount of time while I had the battery out of the truck and load tested at a reputable shop. Or as others on this forum and others have experienced a intermittent connectivity issue in the CAN BUS green connector block that sets behind the glove box.

I have also seen a possible PCM flash update that deals with over voltage concerns (TSB: 18-008-2), but even at 15.3 or 16V on my DIC, I never set a check engine / MIL light, only a service Stability control / Service ABS system and the park brake light on. So not sure that it applies. But who knows?

I'm always open to learn new things and if you can help me understand why this is a aux battery problem that's not even connected in the truck anymore, I'd love to hear it.

@HighwayTrout, why do you think I need to replace my main battery again when its 6 months old and it checked out fine on load test and shows 12.7+ volts after being fully charged by a AGM slow trickle battery charger? Also, if you have any comments on why you think the aux battery needs to be the equation, I'd appreciate to hear that as well.

I value everyone's input, but I'm not just gonna blindly follow somebody that says I need to have both batteries replaced in the truck with a main battery that tested well and without a technical explanation on why with so many others who have deleted the aux battery and so many tools that are marketed specifically for removing / disabling aux battery and or stop start on these vehicles with no problems.
 
Last edited:
mtudb24 said:
Not trying to be a smart ass, but I would love to hear the technical reasons why the aux battery needs to be in the equation? Not just because its there from the factory or that's what my buddy from Stellantis said, but electrical / architecture / schematic reasons why it needs to be there, and I am all ears. I am a vehicle wiring engineer by trade for 30+ years for the Big 3. So I would love to understand why.

I have to believe there is a reason why 1000's and 1000's of Jeep JL and JT owners have disconnected the aux battery when it fails and all the reasons why JSCAN / Tazer / and other companies make tools to disable the start stop system and remove the aux battery from the equation who have no issues afterwards. I haven't counted the number of YouTube videos showing how to disable the aux battery and start stop function with no long term issues.

Why after 9 months of disabling the aux battery would the truck have issues? And then 2 days later and ever since, the truck has been fine?

My vote is something related to a possible IBS sensor fault / failure that "reset" itself after being disconnected from the main battery for a set amount of time while I had the battery out of the truck and load tested at a reputable shop. Or as others on this forum and others have experienced a intermittent connectivity issue in the CAN BUS green connector block that sets behind the glove box.

I have also seen a possible PCM flash update that deals with over voltage concerns (TSB: 18-008-2), but even at 15.3 or 16V on my DIC, I never set a check engine / MIL light, only a service Stability control / Service ABS system and the park brake light on. So not sure that it applies. But who knows?

I'm always open to learn new things and if you can help me understand why this is a aux battery problem that's not even connected in the truck anymore, I'd love to hear it.

@HighwayTrout, why do you think I need to replace my main battery again when its 6 months old and it checked out fine on load test and shows 12.7+ volts after being fully charged by a AGM slow trickle battery charger? Also, if you have any comments on why you think the aux battery needs to be the equation, I'd appreciate to hear that as well.

I value everyone's input, but I'm not just gonna blindly follow somebody that says I need to have both batteries replaced in the truck with a main battery that tested well and without a technical explanation on why with so many others who have deleted the aux battery and so many tools that are marketed specifically for removing / disabling aux battery and or stop start on these vehicles with no problems.
Click to expand...
www.stellantis.com

Contacts

Contact information for Stellantis and its automotive brands
www.stellantis.com www.stellantis.com
 
You must log in or register to reply here.
Top Bottom