Well, I guess this explains the odd electrical issues recently.....
'21 Jeep Wrangler Sport Aux Battery
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4wd
$50 site donor 2026
4wd
$50 site donor 2026
If I had a lift like you - I’d snatch that lawn mower battery from under the plastic fender - tape off the leads. I did the N1>N2 with starter cable - but they are side by side and a 2 hole copper bar would be cleaner …
Please see my other posts about this situation; taking that battery out of the loop is probably your best option… Several videos on YouTube how to do it.
Thanks all. Just out of warranty so I will look into alternatives. The replacement aux was ~$149 from NAPA, however this fault somehow caused the main battery to fail. That was replaced w/ a larger H7 AGM.
Getting at the aux is a pain also, you are either removing the fuse box, undoing a number of harness plugs (made me nervous) or from underside which requires pulling the fender liner and remove/replacing a few plastic pull rivets.
Oddly, the car never gave a battery or other warning, the stop/start just became inop which was fine with me. After the main battery was replaced, I did start monitoring running voltage which would start at ~14.1 then level at 13.7-9, but occasionally drop to ~12.6 or so. That got me looking for the problem.
Don't get me going on stop/start w/ a manual transmission.....
Getting at the aux is a pain also, you are either removing the fuse box, undoing a number of harness plugs (made me nervous) or from underside which requires pulling the fender liner and remove/replacing a few plastic pull rivets.
Oddly, the car never gave a battery or other warning, the stop/start just became inop which was fine with me. After the main battery was replaced, I did start monitoring running voltage which would start at ~14.1 then level at 13.7-9, but occasionally drop to ~12.6 or so. That got me looking for the problem.
Don't get me going on stop/start w/ a manual transmission.....
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is still in there!
That sounds excruciating.
I've heard this is one of the better ones, but haven't done all my research
https://www.smartstopstart.com/jeep-dodge-chrysler-products.html
A buddy of mine just lost both batteries. They live in parallel so if one starts to go it drags the other down with it. He did the mod to replace the primary and disable the aux.
The gladiator itself runs fine but the vehicle electrics don’t. The radio in particular seems impacted. He leaves AS/S enabled and just drives it. Based on this, he plans to go back and add the aux back in. The vehicle did give him dashboard warnings for months that the aux battery was weak and AS/S was disabled. Had he replaced the Aux battery, it probably would not have drained the starter battery.
It looks like when the engine shuts off, a relay separates vehicle systems to the aux battery so the voltage doesn’t dip while it starts off the main. All things considered, that’s pretty cool. I think they could have managed better by also separating them during power off.
The gladiator itself runs fine but the vehicle electrics don’t. The radio in particular seems impacted. He leaves AS/S enabled and just drives it. Based on this, he plans to go back and add the aux back in. The vehicle did give him dashboard warnings for months that the aux battery was weak and AS/S was disabled. Had he replaced the Aux battery, it probably would not have drained the starter battery.
It looks like when the engine shuts off, a relay separates vehicle systems to the aux battery so the voltage doesn’t dip while it starts off the main. All things considered, that’s pretty cool. I think they could have managed better by also separating them during power off.
4wd
$50 site donor 2026
What’s the latest? - if you see my post - once you remove the Aux14 and tape up the leads - run a short starter cable N1>N2 and a new AGM H7 will handle it all … it’s been 2 years with zero issues for me …
To follow up, this is the one I chose. Very, very well made, OEM appearance, and simple install. Thx!
