1990 renix electrical issues

[ZachariaairahcaZ]

Hey, just got a membership first post, hoping someone can help.

I have a 1990 renix xj. Was out wheeling last week and Jeep died. Swapped relays around, no dice. No power to anything inside, no fuel prime. Was getting dark and decided to tow it to trailhead. At the trailhead I noticed that the battery downholder had lost a nut and was touching the positive terminal. I believe the Dow holder was grounded through a bracket and I heard a relay turning on and off when the post touched the Dow holder. Disconnected battery to tow home.


Once the Jeep was home I started troubleshooting.

-the only thing that seems to have any power is the warning light cluster, buzzer and under dash light. No radio, no gauges(fuel shows 3/4, but does not change), no clock

-swapped out battery, I think a cell shorted out
-checked all starter relay post fuseable links for resistance (slightly higher than 0) and voltage. I had 12 volts before and after fuseable links
All fuses in fuse block check good for continuity/resistance
-a few weird things occurring…seat belt light and weak buzzer come on when pushing brake pedal. Weak buzzer noise when opening door. Louder buzzer noise when headlight switch is turned on. However no headlights.
-checked for burnt/dirty wires or plugs at ignition switch, relays, fuse block. None found.
-jumped/bypassed ballast resistor. !!!After jumping ballast resistor I am now getting weak overhead lights and a weak prime from fuel pump. After turning key on and off to prime several times xj now starts and runs, but still no power to electrical systems.
- engine revs fine but will slowly die if door is opened or headlight switch is turned on.

Seems like it could be a ground but I just changed all my battery cables including engine bay grounds using k-suspensions battery cables. Or a short somewhere I haven’t looked.

Weird that jumping the ballast resistor made the pump able to prime (albeit weakly). I thought ballast resistor circuit was only used during run.

I’ve looked through several similar posts, going to attempt to upgrade fuel pump ground according to cruisers54’s tips.

Any ideas? Going in circles at this point.

 

[ZachariaairahcaZ]

I’m checked fuseable link continuity/resistance,
/voltage drop with no load. Is it possible the fuseable links are bad, but still have some connection until a load is drawing? Maybe why the fuel pump prime sounds so weak?

 

[lawsoncl]

Is it possible the fuseable links are bad, but still have some connection until a load is drawing?

Yes, they could be partially burnt. Try jumpering past them and see if that helps. If you have a meter, start measuring voltage at various points back to the battery ground. The wierdness with things partially working make me suspect you have a bad ground from the engine or chassis to the battery. It could also be a bad ignition switch.

 

[cruiser54]

It really sounds like there is a bad ground as already stated. Multiple components could be trying to use the same ground and causing your issues.