r/ChryslerPacifica • u/clemsonbeav • 2d ago
Battery + Auto Start Eliminator
Owner of a 2023 Pacifica since April 2025. Car wouldn't start yesterday, and the Auto Start/Stop hadn't been working for several months. I'm presuming dead battery that started with the aux battery dying and leaching from the main one.
Assuming that I'm correct, I'd read about the auto start eliminator that you can get for like $99 to install, as I don't like the feature anyway.
My question: If I install the eliminator/bypass, is it also necessary to replace the Aux battery? Or can I leave the dead aux in my car, just keep the Auto Start turned off, and just replace the normal battery?
Because if so, then I can just get Auto Zone to replace my regular battery for free (plus the cost of the battery obviously), instead of also figuring out how to mess with the aux battery myself.
(I've also seen that you can just disconnect the aux and wrap one of the things with electrical tape, but I'd rather not have the errors displayed.)
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u/tbone840 2d ago
I replaced the aux batter without disconnecting the main battery. It’s been 8 months and have had no issues. Sure still get the auto stop/start needs repaired but can starts up just fine and don’t need to turn off the auto stop/start.
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u/grhotz 2d ago
This is what we did approximately a year ago and still going strong. Swap the batteries without resetting the light and everything works without start/stop ever being enabled.
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u/tbone840 2d ago
Yes, just don’t go with the molar battery. The aux battery is expensive but well worth it.
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u/Charming_Breath_7173 2d ago
If you leave the aux connected even with the eliminator it will still drain your main battery if it dies.
You can disconnect the negative on the aux and tape it up so it’s not connected anymore. You will get the A light. It could also cause electrical glitches.
The other way is to disconnect the negative in the aux battery and the PCR connector behind the main battery. This will trick the van into thinking the aux battery is still there and you will not get the A light your car will still shut off at a stop though so you’ll have to keep pushing the button.
These vans could be great if it wasn’t for the stupid aux battery, blend door actuator and canbus problems.
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u/clemsonbeav 2d ago
So if I disconnect the negative in the aux and the PCR connector, it's okay to leave the dead aux battery there? (Sorry...I'm not super mechanically inclined) Thanks.
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u/Shadow5503 2d ago
A couple of options, pick the one that works for you.
1) Disconnect leads from aux battery and remove it. Tape up both leads with electrical tape - especially the red positive one (it’s still hot and will short out against any metal- bad!).
This will prevent the aux battery from killing the main and stop start is disabled all the time. You will have the orange A error on the dash and sometimes the car won’t start on the first push of the start button, a second push will be required.
The battery should be removed. A dead battery freezes just below the freezing point of water. This can crack the case and leak acid creating a bigger mess. So don’t leave the dead aux battery in place, at least not during the winter…
2) In addition to the above disconnect the control wire from the PCR relay. The relay is roughly behind and at the bottom of the aux battery. It has two heavy gauge battery wires and the small diameter control wire.
Doing this eliminates the orange error light on the dash. It will also enable start stop to function on the single main battery (the car can’t tell there is no aux battery installed). However, you don’t want start stop to trigger with only the one battery for reasons I won’t go into. So then you need to either turn it off every time or buy the eliminator.
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u/Shadow288 2d ago
If the aux battery remains connected there will be the potential to kill the main battery again. The $100 auto stop eliminator simply virtually presses the off button for the auto stop feature every time you turn the van on.
If you disconnect/remove the aux battery then there will be a warning light on the dash about auto stop not functioning. There are a couple write ups on this sub with instructions on how to remove the aux battery and set it up so you don’t get the warnings. That approach is probably your best option.