ZJ wire harness, more than meets the eye...

tommy54

New member
I have a 94 ZJ with that came down with the rather usual door harness problem. I repaired it once with butt connectors, and it worked for a year or so. I parked the jeep for a year and then tried to get it ready for the road again. Now everything quit working. I took the harness out of the jeep completely and soldered the wires back together, adding wire where the old stuff was no good. It bench tested perfect, perfect continuity even when i moved the harness all around. When I put it back in the jeep a few things worked. a couple windows would go down but not up, the locks would not work, the mirrors would not work. When I try the windows that don't work, the dome light dims and the ABS light comes on. What does the ABS light have to do with anything? Anyone had this problem? I thought this was a simple fix, but something went wrong. Any tips would be great.
 

As difficult as it sounds, i would use a multimeter to test all the circuits on that harness, specifically grounds. If that harness is so worn out that you had to patch it up multiple times, i wouldn't doubt that you missed a circuit or two.
 
I bench tested every circuit in the harness(used a multimeter to test for continuity on every wire from both sides of the harness while moving the harness around) and it is absolutely perfect. no matter how much I moved the harness around I never lost continuity. I could understand one circuit on the body side of the harness shorting out and causing one or two things to stop functioning, but how did the ABS system get involved?
 
Never seen exactly the same thing, but I'd ohm test it instead of a continuity test. Paying real close attention to the grounds. Grounds can really screw you over, when a ground goes bad (or just gets a high resistance) some circuits try to take strange paths to ground.
On other models of Jeep I've seen some strange things happen on the harness where it goes under the carpet on the drivers side. The splices get green and funky looking, the electricity can take some strange paths.
I once put a sheet metal screw through the harness under the drivers side door jam. Had all sorts of really odd things going on.
May not be the harness may be the relays.
Just some fresh ideas that may or may not be helpful.
I've likely spent more time troubleshooting Jeep electrical systems than I have trying to make babies, with a whole lot less satisfaction. :) Time consuming and frustrating, I always seem to win out in the end though..
 

Finding the relevant circuits that the components have in common in failures may lead you to the source of the issue. The ABS system has inputs and outputs that's sometimes shared with other components that may or may not be a component that is directly related to its function such as the BCM, PCM, TCM and instrument cluster. A ground fault can cause multiple issues to components that spreads like wildfire when actuated. The dimming symptom can be caused by a partial short to ground or an open.
 
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