Parasitic Draw Mystery

[AlexJordan22]

Working on my 84 GW and trying to track a battery drain issue I've been having. If I leave the jeep for a couple days my battery will be totally dead. Last time I measured it after it sat for 4 days it was down to ~3 volts. I have since bought a battery maintainer to keep it charged when sitting. When running it has been charging fine but once its turned off it will drain the battery. Relevant details:

Ammeter bypass done by cutting large red wire going from alt - ammeter and attaching it to the solenoid post. Left yellow wire intact and connected red and yellow to one post on the ammeter. All other wiring is factory.

I hooked up my meter and show a 200mA draw. I went and started pulling fuses - none of the fuses made a difference. I then unbolted the firewall connector and it also did not make a difference.

I disconnected the alternator and the draw went away. I did some testing to see if the diodes had failed and it appears they were fine. Took the alternator to have it tested and it tested good at 2 different parts stores. For good measure I bought a new diode trio from Napa for $7.50 and replaced them - it made no difference.

I installed a different alternator (a good cs144 with the adapter) I have and it did the exact same thing leading me to think its not the alternator.

The weird part is that it seems as though I have two separate parasitic draws but they both draw the same amount regardless if both are present (if that makes sense)

For example - with the alternator not hooked up and the firewall connector bolted in I show the draw of 190-200mA. If I disconnect the firewall connector and hook up the alternator I still show a draw of 190-200mA.

If I hook up the alternator and install the firewall connector I still show a draw of 190-200mA. The draw will go away completely if I remove the yellow and red wires from the solenoid.

I removed the plastic wire loom covers and traced the yellow wire to ensure it wasn't spliced in anywhere it shouldn't have been and it wasn't. It was factory spliced to a red wire near the solenoid and then it was just a solid yellow wire going all the way to the firewall.

I'm lost at this point. I even tried disconnecting the yellow and red wire from the ammeter completely and it didn't change the draw. Anything I missed please let me know. I appreciate the help

[tgreese]

Not obvious to me how you can have both the bulkhead and the alternator sinking current and it not be additive.

I would point out that, if you tie the two ammeter posts together and move the charge wire to the solenoid, there is no longer any sink through the bulkhead AFAIK. Current now goes to the dash and lights through the yellow wire, and the bulkhead now only sources current, no sinks. Maybe that's the explanation for what you observe.

I would start by current testing the individual wires on the alternator. You have an excite wire, a voltage sense wire, and a charge wire. Pretty sure if the excite wire stays high, you will power the regulator whether the engine is on or not.

[AlexJordan22]

Right, I agree you would think it would be additive and not remain the same.

What is the procedure to current test each alternator wire?

[letank]

Probably a wild guess, but do you have headlights relays with direct feed from the battery, these can short and drain about 0.1 A each...

[devildog80]

Wellllllll.......I have the same issue on my '84 GW, went through everything & more like you did, never found the issue. So.....wired in a disconnect switch off battery ground, so I can completely shut down all power when truck is off. When I did this, I ran another ground to the body, and found my dome light (some gauge cluster lights, rear cargo light too) actually worked and thought this was the draw, but shut the dome light off and still have the draw.....somewhere.
I am sure we will both find the source someday, in our respective rigs, but until then this is my temporary solution to maintain my battery and be able to drive the truck.

New ground connector on battery, with red cable as a ground (friend donated so used what I had on hand) that connects to new cutoff switch in the cab.
20240422_092946 by Scott Weckerly, on Flickr

Drilled a hole through floor, to mount cutoff switch in cab. Labeled off as tank 1, and on as tank 2.
20240422_092814 by Scott Weckerly, on Flickr

I had some semi truck battery cables 12 ft long in my rig as extra parts when I got it, so used one of these for the ground back to the block but on drivers side now, from cutoff switch (bigger grayish colored cable in pic). Short black cable is new ground to body I added, and as said above found I have more interior lights now working, than I had before adding this. The other black (RED) cable is feed direct off battery ground.
20230820_121242 by Scott Weckerly, on Flickr

The red light temporarily zipped to the steering wheel tilt stem, comes on when I turn my disconnect switch on, to run the truck. Visual reminder for me to kill power when shutting truck off, so battery does not run down.
20240422_092832 by Scott Weckerly, on Flickr

[AlexJordan22]

Probably a wild guess, but do you have headlights relays with direct feed from the battery, these can short and drain about 0.1 A each...

I don't *think* so. Looking at the wiring diagrams on Oljeep.com doesn't show any relays and AFAIK none have been added.

[tgreese]

Re testing each alternator wire -

You've already tested the charge wire, I presume. First I'd unplug the small wires and see if the drain changes through the charge wire. Then I'd make jumper wires so I could put my meter between the plug and the alternator. I'd likely use clip leads (carefully).

I'd comment that I've had alternators that were leaky and drained the battery. Looking at the circuit diagram for the alternator in the TSM, half of the bridge is always blocking the battery connection. There is a capacitor across the bridge that could go leaky. I suppose one of the bridge diodes could go partly or fully shorted and leak, but that would change when you change the alternator. The sense wire is always high, and there is only high resistance to block that. Not 200ma though, unless something is wrong in the regulator.

[AlexJordan22]

Re testing each alternator wire -

You've already tested the charge wire, I presume. First I'd unplug the small wires and see if the drain changes through the charge wire. Then I'd make jumper wires so I could put my meter between the plug and the alternator. I'd likely use clip leads (carefully).

I'd comment that I've had alternators that were leaky and drained the battery. Looking at the circuit diagram for the alternator in the TSM, half of the bridge is always blocking the battery connection. There is a capacitor across the bridge that could go leaky. I suppose one of the bridge diodes could go partly or fully shorted and leak, but that would change when you change the alternator. The sense wire is always high, and there is only high resistance to block that. Not 200ma though, unless something is wrong in the regulator.

I understand, so basically the same thing as testing for leakage at the battery terminal except the battery is fully hooked up and I set the meter between each wire and its connection. Easy enough, I'll do that today and see what it shows

[AlexJordan22]

Wellllllll.......I have the same issue on my '84 GW, went through everything & more like you did, never found the issue. So.....wired in a disconnect switch off battery ground, so I can completely shut down all power when truck is off. When I did this, I ran another ground to the body, and found my dome light (some gauge cluster lights, rear cargo light too) actually worked and thought this was the draw, but shut the dome light off and still have the draw.....somewhere.
I am sure we will both find the source someday, in our respective rigs, but until then this is my temporary solution to maintain my battery and be able to drive the truck.

New ground connector on battery, with red cable as a ground (friend donated so used what I had on hand) that connects to new cutoff switch in the cab.
20240422_092946 by Scott Weckerly, on Flickr

Drilled a hole through floor, to mount cutoff switch in cab. Labeled off as tank 1, and on as tank 2.
20240422_092814 by Scott Weckerly, on Flickr

I had some semi truck battery cables 12 ft long in my rig as extra parts when I got it, so used one of these for the ground back to the block but on drivers side now, from cutoff switch (bigger grayish colored cable in pic). Short black cable is new ground to body I added, and as said above found I have more interior lights now working, than I had before adding this. The other black (RED) cable is feed direct off battery ground.
20230820_121242 by Scott Weckerly, on Flickr

The red light temporarily zipped to the steering wheel tilt stem, comes on when I turn my disconnect switch on, to run the truck. Visual reminder for me to kill power when shutting truck off, so battery does not run down.
20240422_092832 by Scott Weckerly, on Flickr

Funny, I thought about that as a solution as well. Right now I've just been removing the red and yellow wires from the solenoid when I park it but having a switch inside would be much easier. The light as a reminder is a nice touch too! Hopefully one of us can figure it out soon.

[devildog80]

I spend weeks, across 4 different forums, internet searches, articles read, videos watched, and went trough so many checks that had no good results with my situation. I know it is a band-aid fix for now, but moved on and have the truck running/driving/getting smiles per mile, and not just sitting in the driveway tore up chasing unknown electrical issues. Another day for sure, as I still have much to do, and might resolve itself when other electrical issues are buttoned up, or troubles found and repaired.
And kudos to all of the folks who assisted/got frustrated with me when I went through this just last year, as they are professional in their advice, so try to follow their lead carefully. Read the advice, read it again, and then read it again, as I missed so much reading it the first time, and spent a lot of time re-reading information 2-3-4 times more while looking at my wiring, to get it to finally sink in.
Super helpful for sure, to have so much shared knowledge, and wish I could thank each of those people personally for putting up with me through my process.
Good luck

[AlexJordan22]

I did see a couple threads that sounded like a similar issue, I'll go through yours and see what was said

[AlexJordan22]

I spend weeks, across 4 different forums, internet searches, articles read, videos watched, and went trough so many checks that had no good results with my situation. I know it is a band-aid fix for now, but moved on and have the truck running/driving/getting smiles per mile, and not just sitting in the driveway tore up chasing unknown electrical issues. Another day for sure, as I still have much to do, and might resolve itself when other electrical issues are buttoned up, or troubles found and repaired.
And kudos to all of the folks who assisted/got frustrated with me when I went through this just last year, as they are professional in their advice, so try to follow their lead carefully. Read the advice, read it again, and then read it again, as I missed so much reading it the first time, and spent a lot of time re-reading information 2-3-4 times more while looking at my wiring, to get it to finally sink in.
Super helpful for sure, to have so much shared knowledge, and wish I could thank each of those people personally for putting up with me through my process.
Good luck

I made some progress on this and I'm curious to see if it helps you too. When I first started fixing up the jeep I welded a bolt to the body and one to the frame and tied all my grounds to those. The engine to body, body to frame, and negative battery cable all went to the same bolt along with cleaning up other grounds.

So I figured my grounds are all solid. Well on a whim I set up my meter in line with the negative battery terminal and took a spare 4 gauge wire and touched it to the alternator body and the negative terminal and my draw totally went away. It appears as though my engine ground wasn't doing as good a job as I thought (probably because I just cut and put a new end on the factory ground wire which must be all corroded). So I ran a brand new large ground wire from the back of the alternator to the negative battery terminal to ensure its got a solid ground. At this point it looks like it may have fixed my issue so I thought I'd let you know.

[devildog80]

That is great news. I will look at my set up, and see if your resolve will work for my rig.