Issues with a parasitic draw

sam24th

NAXJA Forum User
Location
charlotte NC
Ok so I got an issue I can't seem to figure out. The jeep in question is my 1990 Jeep Cherokee Laredo with all factory Renix computer systems. So my issue is that if I leave the Jeep for more than 3 days the battery is completely dead. So far Ive been disconnecting the battery when I don't drive it as a temporary thing so I don't kill the battery cells. I don't have any aftermarket equipment currently hooked up to it and even took out the radio to eliminate the constant draw for the headunit. I tried the pulling fuses trick with a testlight/multimeter hooked up between the neg batt cable and the battery terminal and none of the fuses do squat I am still drawing a lot of power. I know drawing a small of power consistently is normal but it seems to be drawing a lot more than it should be. I actually traced my issue to the power distribution block on the passenger side. There are 3 wires that are currently drawing power from the block with key off but I have no clue what they are or where they go. One of the three wires draw the most power power which is the one I suspect as being the culprit but not sure of what it does exactly. Any further assistance with the matter would be awesome at this point.
 
I had a similar problem once which got worse over time (down to 2hrs). It was the battery itself. Though if you've been disconnecting the battery and still having the problem, maybe this can't be the case.
 
I didn't disconnect any relays and the wires don't go to relays or atleast that I can see. The wires in question are have fusible links coming from the power distribution block located passenger side wheel well. The one connector I was talking about drawing the most power has 2 red wires and 2 fusible links inline with it. Also with this one wire disconnected the jeep doesn't do squat with the key in the run position not even crank over.
 
One at a time, try pulling every relay under the hood, and if one clicks when pulled and reinstalled you have isolated it further. If it does not click, it could still be a stuck closed relay!!

Using a relay diagram (side of the relay) look for a NO relay that is now NC, and therefore stuck closed, and therefore powering something like the O2 sensor heater.

Those wires do eventually go through relays!!!!!
 
Alright cool ill try that tomorrow and report back. Didn't really think to check those.
 
Do you have anti-lock brakes?
 
Off the PDC/Starter Relay you have four ring connectors.

The single is to the alternator.

One of the double-wire sets goes to the ignition switch/fuel pump relay, transmission control unit, and other things.

One of the double-wire sets goes to the fog lamps, fuse panel, engine compartment lamp, anti-lock brake pump/ignition off draw connector, anti-lock brake relay "B".

One of the double-wire sets goes to the "B" Latch relay/efan control relay.
 
Nope no antilock brakes. Also don't have fog lights either. But those wire sets sound like what I'm looking at. Gonna try pulling relays tomorrow evening and see where that gets me. I did recently replace the alternator if that may have anything to do with it. Jeep is charging up by itself though so the alt does work.
 
Do you have the power antenna? Mine went bad and would constantly run. Killing the battery a few times. There is a relay for it under the dash
 
Hmmm, I remember seeing somewhere that somebody had a similar problem and disconnecting the lighter and accessory power solved it. sounds weird, must've had a short but..
 
Nope no power antennae. Anyhow I kinda hit a wall with trying to diagnose the problem today. While out in the garage I hooked up the meter like previously between the battery terminal and ground cable and began pulling relays in the engine bay. Well I wasn't really paying atention but I must have burned out the meter because it wasn't reading anything. Opened up the meter and fuse blew, replaced the fuse but it refuses to read anything even when i put it on voltage and try to measure battery voltage. So looks like I need to get a new multimeter tomorrow. On a side note though, I tried listening to see if any of the relays clicked when I removed them and I couldn't hear any of them click. Doesn't mean they aren't stuck though so I can't rule that out just yet. Gonna have to get a new meter tomorrow to confirm.
 
My 90 will die after a week or so. I have never really found the issue and it has never gotten worse. I just hook up the battery tender when I park it for more than a week.
 
Eh if I dont figure it out ill just disconnect the battery when I don't drive it.
 
So this was a million years ago and all, but did you ever track it down? I've got a very similar behavior on my '89 that I'm trying to figure out.
 
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