Battery drain sources?

I have 1 rig that is recently (it is new up In Co Springs), and two with me that for a good while, have been draining good batteries (two were/are pretty new) in a day or two or week or a month when not used daily. And I mean drained the battery completely.

One is an 85 Cherokee 2.5 L (was gas, converted to diesel). It has a slow short I am trying to locate..Kills a 1000 amp hour beast in 2-3 days.

One is a new one I bought 4 years ago that keeps eating batteries in storage, 87-4x4-4.0 L, but it drained a new one in a week recently, when it had not been giving me problems for the last 2-3 months (but had killed batteries before) so the problem is intermittent. The last 3-4 days no problem.

The third is new to my Daughter out of town, 1000 miles away, 89 Cherokee, 4x4 w/4.0so debugging it remotely on Co Springs. It is intermittent I think, draining a charged working battery in 2-3 days.

I need help creating a complete list of usual and unusual (mine at typically unusual LOL) suspects.

So far I have:

Door switches to interior lights sticking.

Stuck brake switch light.

Headlights left on (this has not been the issue on these and have not caught the first two in the act yet)

?????????

Shorted wiring (such fun)

There are no alarm systems, or aftermarket do-dads on them

I know how to isolate power drains at the battery, but so far these seem to be cloaked night time gremlins that have vanished when we look for them, except the 85, I am trying to track it through a mess of wiring into the dash......

We had a ford Taurus and Chrysler 5th ave that shorted somewhere activating the cruise control even with the vehicle off. The Chrysler only caught because it because the curse control actuator was loud when the battery was re connected.
The ford tried to accelerate into my sisters dorm at college, damn car would suddenly accelerate like it was on a interstate on ramp. Tapping the brakes did disengage it, didn't respond to switches either. crappiest car ever.

Never had issue with the 91 up jeep cruise control, but it could be worth checking if your rigs have it.


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Glove box light is common among all cars. Best way to check is to voltage drop all fuses. A fuse with no current flowing will show 0 v. A fuse with current flowing will show about 1-5mV. Pretty much how I start all my parasitic draw diag.

Don't rule out alternator or starter as a draw either.

When this has happened to me it has been the batteries themselves, but agree that there are some phantom draws that can make the battery go dead.

One to check is the under hood light. Another is the blower motor control. I had a fun one tracking down a battery drain on my moms GC. Went to look under the dash on the pass. Side and herd a hum. Pulled the lower intake off the blower motor and it was spinning slowly , maybe 100-200 rpm. Can also be a radio but doubt it. What I would do is do the parasitic draw test with current. Use the meter In line with battery pos. And start pulling fuses. If nothing happens disconnect the meter and unhook starter and alt. If the current drops you found it's one of the two.


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power antenna? that was the issue on mine

I vote glove box too...since it's happened to me twice...on two different Jeeps. The little plastic adjuster for the latch gets loose. Just a stab.

The last hard one I found was the wire splice (s) under the carpet on the drivers side. Carpet stayed soggy from me tracking in rain and snow, those splices were green and crusty, I could actually here the splices crackle as they arched to ground when I was close enough.

I had a tough one with the rear hatch. The latch was loose, so when the wind blew and the hatch moved the light would turn on and drain the batter. Very hard to detect

Got a multimeter? Unhook the neg terminal and hook it up to read DC amps in series with the neg terminal and neg cable give it a minute to shut down any computers in the car and start pulling fuses till you see the amperage drop. than whatever is on that circuit is your culprit. resting amperage should be around .030 amps

xCWolf said:

Got a multimeter? Unhook the neg terminal and hook it up to read DC amps in series with the neg terminal and neg cable give it a minute to shut down any computers in the car and start pulling fuses till you see the amperage drop. than whatever is on that circuit is your culprit. resting amperage should be around .030 amps

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