Unexplained power drain?

Having a problem with significant battery drain, it sat for a few weeks after the new battery was put in, went to start it and was dead. Put the battery on the charger and charged to full charge, drove it yesterday the volt gauge was reading I’m guessing about 12v, put it on the charger again and it was charging at 3-5 amps. Its a 94 XJ Sport, new yellow top optima, mean green alt installed last summer and upgraded all cables, new starter installed early spring.
Got the volt meter out and this is what I found:
Set up: Positive battery cable disconnected and the positive lead of the voltmeter connected to the positive terminal on the battery (negative battery cable connected), while holding the negative lead of the voltmeter along with the fuse block cable between his fingers he would get 0v, but if hubby touched his arm to the body of the Jeep he got a reading of 9v. I tried the same and I only got .02v, guess I am not as conductive has the hubby…


Positive lead on the voltmeter connected to the positive battery terminal, negative lead on the voltmeter connected to the fuse block cable with all fuses pulled reads 0v.
I put each fuse in one by one (separately) and got this:
60A Alternate power 2 = spikes immediately .5v then decreases to .04v
40A Heat rear window = .0v
60A Ign System = .02v
40A Headlamp System =.02v
20A Hazzard Lamps = .01v
40A Fuse Block = 12.8v
30A Engine Control 1 = spikes 12.8 then decreases
60A Alternate Power 1 = Spikes to 7v then decreases to .04
All of the relays = 0v

When all fuses are plugged in it reads 12.73v then very slowly decreases.
Also the small yellow fuse (20a) for the I.O.D something or other reads odd depending on what other fuses are also plugged in….what is this I.O.D fuse for?

So with all that info, could there be a problem with the fuse block? I know there are live volts running through various components but electronics is not one of my strong points.
Any ideas on where my power drain might be coming from or what I should look into further? Could it be as simple as a bad ground somewhere?

Thanks!!!

Try testing for parasitic load.. Take your dvom and put in series (positive and negative inbetween the positive battery post and the positive cable) of the battery.. Be sure to have your dvom setup in amps.. if you flow more than 1.0 amp yo have a parasitic draw..Then start pulling fuses (one at a time) till you get to a normal reading (1amp or less)..Take note of which fuse you pull..When the amps drop you have found your suspect circuit.. Then start looking for shorts on that circuit..

I.O.D is basically your dome lights and stereo memory and the like. its there to keep the truck from draining the battery while being transported from the factory to the dealer. it was usually installed at pre-delivery inspection.
definately need to do the above mentioned parasitic draw test. although I think that 0.5a is the threshold.

I chased a power drain issue for a long time, even taking the Jeep to several shops including one that specialized in electronics. No one could figure it out. I found the culprit on accident as I was walking by the passenger side front fender. It was the power antenna, which would cycle once every 30 to 40 seconds. Everyone was looking for a constant drain, so that's why it was elusive. Anyway, perhaps something to check if you have a power antenna. Good luck.

Thanks for the advice, I will try this out tomorrow.

Michelle, you removed the doors correct? What did you do with the pin switches?

xjtrailrider said:

Michelle, you removed the doors correct? What did you do with the pin switches?

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I didnt do anything with the pin switches....

That could be my problem, I removed the interior lights last year and it never occured to me that when you open doors (or remove them) that the lights would come on therefore having no lights :idea: haha light bulb momnet! I'll look into that when I got home from work today.
Thanks Jon, look forward to seeing you and your new rig up on the mounitan Saturday.

DAZYDG said:

I didnt do anything with the pin switches....

That could be my problem, I removed the interior lights last year and it never occured to me that when you open doors (or remove them) that the lights would come on therefore having no lights :idea: haha light bulb momnet! I'll look into that when I got home from work today.
Thanks Jon, look forward to seeing you and your new rig up on the mounitan Saturday.

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No problem! Yep its been a while since we have wheeled together, looking forward to it!