76 Cherokee Electrical Gremlin Assistance

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CBJoe
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76 Cherokee Electrical Gremlin Assistance

Post by CBJoe »

Hello Folks...looking for some assistance chasing down an issue that is so easy its hard. :oops:

Recently I had posted about a classic starter/ignition issue where the starter just kept running even with key off. That issue seems resolved, but twice now about a week apart, I came to the jeep and the battery was completely dead dead dead...replaced battery a week ago as it had a dead cell (10.8V max). Went to dinner the other night and came back to jeep and again brand new battery was kaupt. Completely dead again. This last time the Jeep started strong and drove 5 miles to destination and then sat for about 3 hours while at dinner. Battery was swapped out with another brand new one...but I'm concerned about killing this one as well.



2 weeks ago I replaced the following items:
- Turn Signal Switch
- Starter solenoid
- ignition cylinder / Key

Things I've checked/done:
- Alternator seems to be consistently working and producing 14.8-15V
- I can find no parasitic battery drain with my meter and key off.
- I'm having no issues with fuses blowing

This jeep is about as basic as can be electrical wise....
- DUI Distributor w/ relay installed to provide power.
- Ammeter Bypassed
- Does have a radio and Amp....but I can find no evidence that either remain powered on with key off.
- I have door switches disabled so interior lights only come on when I manually turn on with headlight switch.

I'm going to go back through the work I did replacing the turn signal switch. But I cant imagine that would cause this. And wouldn't any 12V shorts to ground cause fuses to blow as opposed to draining battery?

At this point I feel like I need to make a list...where everytime I turn off the jeep I'm going to go through a checklist
- Verify no lights on dash
- Verify Amp and Radio Off
- Verify rear window motor doesn't operate
- ???? what else ???

I'm about to replace the Relay to distributor and ignition switch just because....All I can imagine is a relay is hanging and putting power somewhere where I cant visually see it (like lights or radio).

Would love to hear if anyone has other ideas on what to check.

Joe
1976 Cherokee Chief / Stock Q-Trac, Stock 360
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tgreese
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by tgreese »

Measure. Measure, measure, measure. Divide and conquer.

A car battery had something like 600 amp-hours of power; 60 hours at 10 amps, though at half-discharged it may not have enough current to spin the starter.

Disconnect a battery cable from the battery. Touch the cable end to the post briefly and look for a spark (possible).

If you see a big spark, use that as your indicator and start disconnecting things until the spark goes away. Otherwise you can use your meter. Do you own a multimeter? Use the AMPS scale to check for battery drain.

Start on the higher AMPS scale (usually 10 amps). Plug into the AMPS connections on the meter and put your meter in series, one lead to the disconnected battery post, the other lead to the disconnected cable. The current need to go through the meter to measure amps.

If you have a current reading, that will give you an idea of how much time to drain the battery. I would start by disconnecting the alternator. These can have bad components and drain to ground. Then start pulling fuses, disconnecting connectors, etc. Realize there are three main harnesses: under-hood, dash/cabin, and rear of car.
Tim Reese
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CBJoe
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by CBJoe »

Hi tgreese,

Yessir...I have a quality multimeter. So far I have been unable to identify any consistent battery drain with the meter. When the ignition is ON (but jeep not running) I get about 3-4amp draw. But in OFF it drops to maybe 150mA and then zero draw. I think whatever issue I have it isn't consistent.

Very frustrating...I'm going out in a bit to go through all the work I did before on in the steering column. I'm just trying to think though what electrical draw there could be that doesn't show itself in the form of lights being on or motors powered (eg. the rear window).

Joe
1976 Cherokee Chief / Stock Q-Trac, Stock 360
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devildog80
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by devildog80 »

UGH.....chasing one of my own for longer than I would like....
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified

JWestfall
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by JWestfall »

I just replaced the starter solenoid on my Wagoneer (71) and the new one out of the box was faulty. One of the small posts (forget which one) was hot even with the key out of the ignition. The next one worked fine. Probably not your issue, but you just can't trust new parts out of the box.
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CBJoe
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by CBJoe »

I just re-checked everything I've replaced recently and couldn't find any smoking guns. I went ahead and replaced the ignition switch since I was in there. I think I'm just going to have to monitor super close for a while....and be sure I always have my jump pack on me :lol:

I have a pretty consistent 5-6mA battery draw which I believe is the stereo. I've unplugged the clock as it doesn't work. I just have a hard time thinking of what could only intermittently drain the battery while sitting unless a relay somewhere isn't de-energizing. I would think if this happened to my HEI distributor relay it would mean the car would keep running even when I took the key out (unless I'm thinking way wrong)....

Joe
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Yeller
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by Yeller »

I feel you pain. Check everything and have a 20ma draw, anything under 60ma is more than acceptable. But the battery is dead in 3 days, something is turning on and it is not any of the electronics I’ve added, it’s in the original harness, been doing it since before the engine swap. Super aggravating. Eventually it will get a complete rewire.
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CBJoe
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by CBJoe »

Yeller wrote: Tue May 30, 2023 4:07 pm I feel you pain. Check everything and have a 20ma draw, anything under 60ma is more than acceptable. But the battery is dead in 3 days, something is turning on and it is not any of the electronics I’ve added, it’s in the original harness, been doing it since before the engine swap. Super aggravating. Eventually it will get a complete rewire.
right? My model jeep is the most basic in regards to relays and such. To be honest I cant think of a relay on the jeep that could be stuck closed randomly without being super obvious (lights on/stereo wont turn off/etc... I'm hoping maybe something was random funky about the ignition switch and replacing it helped. We'll see.

At this point I'm going to double-check the amp draw every evening before I let sit to see if something crops up.

Joe
1976 Cherokee Chief / Stock Q-Trac, Stock 360

Srdayflyer
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by Srdayflyer »

i had a power draw problem trached it down to the clock, i simply removed the clock and installed a factory blank out plate
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CBJoe
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by CBJoe »

I wish it was that ....I unplugged the clock as it didn't work anyway. So it's just sitting there

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67GMC
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by 67GMC »

I made a "tool" with two electrical spade connectors that fit into the fuse box in place of the fuse that was there. Then I could measure the current in particular circuits one by one. This only works for some of the Jeep electrical but helped diagnose a glove box bulb that didn't turn off when the lid was closed(!). If you still have an underhood lamp, disconnect that -they are notorious for staying on with hood closed too.

I also had a bulb the PO had jammed into a socket for the running lights that was the wrong configuration and it shorted to ground and would pop the fuse sporadically. That was an odd find. I didn't drive the Jeep at night that much and as soon as I put the parking lights no, the fuse would pop (but not every time). Connection was corroded and a bump would set it off.

Persistence is key to track these things down. Jeeps are bad for ground issues. I just made a new ground in the rear end by grinding metal on the frame to shiny and installing a stainless steel bolt and nut. Had so many issues with grounds related to trailer hitch wiring and intermittent tail light issues that I just made a new ground point. Much better.

If you do find the cause, please post. Always inspires others in the same quest.
Good luck.
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1987 Jeep Cherokee (XJ), 4.0L I6, Auto, Selectrac
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CBJoe
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by CBJoe »

fingers crossed...but its been almost 2 weeks since issue. Last I changed was ignition switch. Who knows....maybe my random wire tracing and shaking/pulling "fixed" it :lol:

PFM ....Pure Freaking Magic.....hopefully it sticks ;)
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Yeller
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Re: 76 Cherokee Electrical Gremlin Assistance

Post by Yeller »

PFM is always scary, but I’ll take it when it appears lol. Here’s hoping it’s fixed permanently 😆
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909
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