Electrical Nightmare

[Team MP]

2022 Jeep Gladiator Mojave. It is my wife's daily driver and my weekend toy. We never had any issues leading up to this point with any of the electrical stuff. I backed it out of the house one morning after it had been in the garage all night. Everything started and worked fine. I parked it in the driveway, and it sat for maybe 2 hours. When she got ready to go to work, she said the battery was dead. I thought well that probably means the auxiliary battery is dead, so I went and bought a new one. (Side note: changing the aux battery is a huge deal!) I put the new aux battery in but the truck still would not start. So, I went and bought a brand-new main battery because, I heard that when one goes bad, they both go bad and you have to change them at the same time. I replaced the main battery and the truck started, but then I got all sorts of error messages on the dash saying to pull over to a safe location and the truck was going to automatically shut down. Then I read somewhere that when you change the batteries out you should touch the negative battery wire to the positive battery wire for 30 seconds to reset the computer. So I did that and there was a pretty big spark that made me instantly regret that decision. Now the truck won't start at all. I get some dash lights to come on but when I try to start it, it acts like the battery is dead. Won't do anything. My multimeter shows that I have 12.8 volts coming from the main battery terminals and when I leave the negative wire touching the negative, I can get 12ish volts coming from the posts of all the N terminals on the fuse panel. So, I don't think my main fuse is blown, or could it be? I also replaced all of the relays that are related to the Start Stop system and that didn't help anything. I have even tried to remove the aux battery negative wire and pull fuse f42 to bypass the aux battery. When I do that, there is no power to the vehicle at all... What am I missing? I ordered a new main fuse but it won't be here for a few more days, but I don't really believe that is the problem. Also, as a side note, I have a Tazer and thought it might be messing things up, so I "unmarried" it, but left it installed. Does that have any effect? And the new main battery is STD. Does it have to be AGM?? Please help!

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[GrubbyBaja]

Ouch! Sounds like you didn't isolate the Aux battery and shorted the Aux battery through that main fuse array. Main fuse array is definitely blown...hopefully that is all.

 

[Lost1wing]

Ditto on the fuse array.

It is very possible your fuse array was fried after you changed the aux or the main. They don't go bad. They are given the opportunity to fail when owners don't know what they are getting into.

Steps at this point,

Disconnect and isolate both batteries.

Charge both batteries with an AGM charger until 100%.

Replace the fuse array.

If you want to test your original fuse array, you will need a VOM. I would guess two of the fuses are blown.

With any luck, the fuse array was the only damage.

Your IBS should reset if you leave the batteries disconnected for a while. You can disconnect the electrical connector for the IBS to be sure.

Once everything is installed, the last thing to connect should be the negative ground cable. It doesn't matter which end, the one at the fender ground location or at the main negative top plate.

 

[Team MP]

The Fuse Array is the long flat fuse that connects to the "N" posts at the end of the fuse panel right? If the fuse array is blown, would I still be able to read voltage on the posts? There is a small drop in voltage on each of them but they are all still reading over 12 v. My new fuse won't deliver for another 4 days, so I'm dead in the water until then.

 

[Texbaz]

The Fuse Array is the long flat fuse that connects to the "N" posts at the end of the fuse panel right? If the fuse array is blown, would I still be able to read voltage on the posts? There is a small drop in voltage on each of them but they are all still reading over 12 v. My new fuse won't deliver for another 4 days, so I'm dead in the water until then.

That's ashame, looks like you have around 7 or 8 dealers in driving distance from you. So, no stock in any.
Maybe a salvage yard in your area if you feel adventurous.

 

[GrubbyBaja]

With all of the electronic, solid state circuitry, coupled with the N1 terminal feeding those electronic circuits from the Aux battery, you could backfeed voltage through the electronics to the array bus. Upon initiating the electrical system, the electronics (diode circuitry) prevents current flow in the "reverse" direction. Your meter's nearly infinite resistance would prevent enough current flow to trigger the reverse biased circuitry. All this is just speculation based on courses I took 35 years ago which has been mostly erased by beer and sleep.

 

[Lost1wing]

The Fuse Array is the long flat fuse that connects to the "N" posts at the end of the fuse panel right? If the fuse array is blown, would I still be able to read voltage on the posts? There is a small drop in voltage on each of them but they are all still reading over 12 v. My new fuse won't deliver for another 4 days, so I'm dead in the water until then.

Yes, you would still see a voltage reading. As the previous post mentions N1 is not fused. N3 took a hit. Hopefully that is all.

 

[NortonJTSS]

If you reconnected the negative battery cable and suddenly had zero power whatsoever then you probably hooked up the wrong cable. Different model years have been known to switch those around.. does sound like maybe fuse array though

 

[Over The Hill]

WOW. After reading all the horror stories about changing batteries I went to the Jeep dealership.
For a total of $617, both batteries replaced, guaranteed to be done right.
Figure $420 for batteries at Sams Club, my peace of mind was under $200. Best investment in years.

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