3.6L ESS Battery Diagram

TrickyO

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Richard
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On the RHD the Washer water bottle is below the PDC. Crawling under I think the Aux battery is immediately below the main battery. Will be pulling that out to see if I can get to it. If so they have built the RHD with much easier access. Will update after I try.
 

correfe

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By all means if you can do nothing else, unplugging the relay may help, but there is a very limited set of circumstances where just unplugging the relay will improve the situation. If the Aux battery is drained, so is the Main battery because they are connected in parallel. Unplugging the relay will have limited benefit here unless you also disconnect the Aux battery negative, then you only have to charge the Main battery to get going. If just the Aux battery is drained, it means the ESS relay is bad or the ESS fuse is blown, isolating the batteries and preventing just the Aux battery from charging. Unplugging the relay won't help here.

It will help the situation where a bad Aux battery is causing sporadic electronic behavior, as long as the Main battery still has a charge. Even then, disconnecting the Aux battery negative removes any possibility of it impacting starting from the Main battery.

So if you're reading this post and learning about disconnecting the relay to increase your odds of surviving a battery issue, realize that having an adjustable wrench or a pair of pliers in the jeep to disconnect the Aux battery negative increases the odds even more. Or replace the Aux battery negative cable nut with a wing nut, so no tools are needed to disconnect it. And no need to tape or secure the battery ground.
Which one is the fuse for ESS and relay for ESS?
 
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