VIDEO : HOW TO Replace the Main & Auxiliary Battery on a JL Wrangler / JT Gladiator

JAGS

Active Member
Just want to thank Eddie for this great vid. 👍 I was able to swap everything in under 2 hrs start to finish. This alone is an amazing feat. Ha ha. I posted details in my JAGS JL thread.

note: Eddie’s vid is literally the only vid online mentioning the E torx for the aux battery. Saved me a lot of time as I ordered on Amazon and had on hand before starting the job. 😎🤙
 

wayoflife

Administrator
Staff member
Just want to thank Eddie for this great vid. 👍 I was able to swap everything in under 2 hrs start to finish. This alone is an amazing feat. Ha ha. I posted details in my JAGS JL thread.

note: Eddie’s vid is literally the only vid online mentioning the E torx for the aux battery. Saved me a lot of time as I ordered on Amazon and had on hand before starting the job. 😎🤙
Way to go and glad that I could be of help (y)
 

WJCO

Meme King
Well, three weeks left on JT warranty and batteries went out. I was getting a message "Auxiliary Switches Temporarily Disabled - Battery Charging." It would only occur right after starting the Jeep. At first it was every few days, then started to pop up every time I started it. Even after 30-40 miles of driving, the message still appeared. Dealer said both batteries were bad. Glad to have gotten that done.
 

jeeeep

Hooked
Did the batteries swap, it was easy, less than 30 minutes. Changed the battery from the 48 to 92r for some extra capacity for the soon to be added electronics. Also plan to upgrade the alternator to the 240 amp that came with the tow/aux switch group.

Decided to change the serpentine belt, what a PIA that turned out to be. I didn't remove the air filter box, only the tubing, should have removed the air filter box

Have to remove something I think is emissions related under the alternator to get to the belt tensioner, it's 1/2 inch extension and a stiff spring without much movement. While you can squeeze your hand behind the air filter box to reach the pulley to remove the belt, it's easier with the air filter box removed. Once the belt is loosened, remove the alternator and bracket to work the belt out. The belt will not come off with the bracket still in place.

13mm, 15mm, 16mm bolts because it would be too fucking easy to use 1 size bolt for the alternator and bracket.

Put the new belt on, have to make sure it's aligned properly between the tension pulley and an idler pulley that is attached to the bracket removed. I installed the new belt and did not keep it held together so when I put the bracket on the belt ended up on the wrong side of the idler pulley. Undo everything, reinstall belt making sure it's between the tension pulley and idler. Tighten everything up, move the tension pulley to get the belt on the outer pulley and too much slack, the damn belt is too long! I can pull the belt off the outer pulley without moving the tensioner.

Pull everything off again, compare belts and it's at about 2 inches too long. This is the belt size listed for the JL and JK's since 2012.

Will need to get the correct belt from the dealer 🤬

This shit show took 2.5 hours, then another 30 minutes at the auto parts as the guy tried to find a shorter belt before giving up and refunding.

There is an intelligent battery sensor on one of the negative battery connections, I was told if there is belt slippage, it can cause electrical issues and cause the Jeep to not run or start to protect the battery. I'm wondering if the batteries may have been fine and the issue is belt slippage or the sensor may be faulty. The main battery tested at 11 volts before I replaced it and was having to jump it each day. Time will tell.

I miss older Jeeps, they weren't as comfy and nice inside as todays Jeeps but sure a hell of a lot easier to work on. Too many fucking sensors to have to be aware of and careful with.

I plan to test the battery over the next few weeks to see if the pre-start voltage begins to drop.
 

OverlanderJK

Resident Smartass
Did the batteries swap, it was easy, less than 30 minutes. Changed the battery from the 48 to 92r for some extra capacity for the soon to be added electronics. Also plan to upgrade the alternator to the 240 amp that came with the tow/aux switch group.

Decided to change the serpentine belt, what a PIA that turned out to be. I didn't remove the air filter box, only the tubing, should have removed the air filter box

Have to remove something I think is emissions related under the alternator to get to the belt tensioner, it's 1/2 inch extension and a stiff spring without much movement. While you can squeeze your hand behind the air filter box to reach the pulley to remove the belt, it's easier with the air filter box removed. Once the belt is loosened, remove the alternator and bracket to work the belt out. The belt will not come off with the bracket still in place.

13mm, 15mm, 16mm bolts because it would be too fucking easy to use 1 size bolt for the alternator and bracket.

Put the new belt on, have to make sure it's aligned properly between the tension pulley and an idler pulley that is attached to the bracket removed. I installed the new belt and did not keep it held together so when I put the bracket on the belt ended up on the wrong side of the idler pulley. Undo everything, reinstall belt making sure it's between the tension pulley and idler. Tighten everything up, move the tension pulley to get the belt on the outer pulley and too much slack, the damn belt is too long! I can pull the belt off the outer pulley without moving the tensioner.

Pull everything off again, compare belts and it's at about 2 inches too long. This is the belt size listed for the JL and JK's since 2012.

Will need to get the correct belt from the dealer 🤬

This shit show took 2.5 hours, then another 30 minutes at the auto parts as the guy tried to find a shorter belt before giving up and refunding.

There is an intelligent battery sensor on one of the negative battery connections, I was told if there is belt slippage, it can cause electrical issues and cause the Jeep to not run or start to protect the battery. I'm wondering if the batteries may have been fine and the issue is belt slippage or the sensor may be faulty. The main battery tested at 11 volts before I replaced it and was having to jump it each day. Time will tell.

I miss older Jeeps, they weren't as comfy and nice inside as todays Jeeps but sure a hell of a lot easier to work on. Too many fucking sensors to have to be aware of and careful with.

I plan to test the battery over the next few weeks to see if the pre-start voltage begins to drop.
Longest battery swap post on the internet award.
 

wayoflife

Administrator
Staff member
Did the batteries swap, it was easy, less than 30 minutes. Changed the battery from the 48 to 92r for some extra capacity for the soon to be added electronics. Also plan to upgrade the alternator to the 240 amp that came with the tow/aux switch group.

Decided to change the serpentine belt, what a PIA that turned out to be. I didn't remove the air filter box, only the tubing, should have removed the air filter box

Have to remove something I think is emissions related under the alternator to get to the belt tensioner, it's 1/2 inch extension and a stiff spring without much movement. While you can squeeze your hand behind the air filter box to reach the pulley to remove the belt, it's easier with the air filter box removed. Once the belt is loosened, remove the alternator and bracket to work the belt out. The belt will not come off with the bracket still in place.

13mm, 15mm, 16mm bolts because it would be too fucking easy to use 1 size bolt for the alternator and bracket.

Put the new belt on, have to make sure it's aligned properly between the tension pulley and an idler pulley that is attached to the bracket removed. I installed the new belt and did not keep it held together so when I put the bracket on the belt ended up on the wrong side of the idler pulley. Undo everything, reinstall belt making sure it's between the tension pulley and idler. Tighten everything up, move the tension pulley to get the belt on the outer pulley and too much slack, the damn belt is too long! I can pull the belt off the outer pulley without moving the tensioner.

Pull everything off again, compare belts and it's at about 2 inches too long. This is the belt size listed for the JL and JK's since 2012.

Will need to get the correct belt from the dealer 🤬

This shit show took 2.5 hours, then another 30 minutes at the auto parts as the guy tried to find a shorter belt before giving up and refunding.

There is an intelligent battery sensor on one of the negative battery connections, I was told if there is belt slippage, it can cause electrical issues and cause the Jeep to not run or start to protect the battery. I'm wondering if the batteries may have been fine and the issue is belt slippage or the sensor may be faulty. The main battery tested at 11 volts before I replaced it and was having to jump it each day. Time will tell.

I miss older Jeeps, they weren't as comfy and nice inside as todays Jeeps but sure a hell of a lot easier to work on. Too many fucking sensors to have to be aware of and careful with.

I plan to test the battery over the next few weeks to see if the pre-start voltage begins to drop.
Holy hell!! I really do hate how much more difficult it is to work on a 3.6L serpentine belt versus a 3.8L. I'll never understand why anyone would make things HARDER to do when there really is no need for it.
 

CalSgt

Hooked
Pull everything off again, compare belts and it's at about 2 inches too long. This is the belt size listed for the JL and JK's since 2012.

Will need to get the correct belt from the dealer 🤬

This shit show took 2.5 hours, then another 30 minutes at the auto parts as the guy tried to find a shorter belt before giving up and refunding.

So... What is the correct belt length for the JL with 3.6L?

I bought a spare back in 2018 to keep in my "Wheeling away from home kit," now I'm worried its not correct.

Being its a 2018 JL half of the maintenance parts I've purchased over the years (air filters Etc) have been wrong. I started ordering parts for a 2019 instead to ensure they don't give me JK parts.
 

jeeeep

Hooked
So... What is the correct belt length for the JL with 3.6L?

I bought a spare back in 2018 to keep in my "Wheeling away from home kit," now I'm worried its not correct.

Being its a 2018 JL half of the maintenance parts I've purchased over the years (air filters Etc) have been wrong. I started ordering parts for a 2019 instead to ensure they don't give me JK parts.
Was running out of daylight and didn't get a measurement on it. Going to the dealer to get the same part number stamped on the belt and will measure it.

The guy at Autozone tried to locate the belt size but none of the cross reference charts he had listed it. Every other "OE" belt listed was 87.8 or longer. The tensioner does not have enough space to move enough for the extra slack.

here's a picture I took after after removing it to compare the length:

SerpentineBelt.jpg
 
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