Chasing gremlins (parasitic draw) -
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post #1 of 2 Old 06-08-2021, 11:35 PM Thread Starter
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Chasing gremlins (parasitic draw)

I have a power draw in my 89 Comanche, kills my battery if I leave it over night. I tracked the culprit down to my brake. The volt meter show me that when I engage the brake (key off), that the amps jump from .01 on a 20 amp gauge to 8 something. I'm not sure where to start looking to fix it.

Edit: I guess what I need to know is where do all the wires that go from my brake pedal end up? I'm trying to narrow it down before I have to take my whole dash off and just keep chasing gremlins. I'm not even sure it's the brake, but it did make the volt meter jump.

Last edited by Mutt1992; 06-09-2021 at 09:27 PM.
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post #2 of 2 Old 06-09-2021, 11:58 AM
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1987 MJ Comanche 
Join Date: Dec 2012
Location: New Market, MD
Posts: 642
If you don't already have this, I would start with the wiring diagrams for the MJ.

It is for the 88, but 89 should be identical.

One place to start your search is a bad tail light socket or a bad ground in the tail end. For the ground, remove the driver's side tail light and check the ground connection located on the sheet metal.

Be sure to check out Cruiser54 Renix tips at

Lots of videos on youtube for chasing parasitic draws. Watch several of those to determine the best approach to tackle this.


87 Comanche, 4.0, AX15 (formerly BA10/5), D44
84 CJ7, 4.0 (93 XJ) AX15 (Formerly T5)
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