Parasitic Load -- Help!!

OK, I need the help of the experts here - maybe someone else has had this problem and can point me in the right direction.

So, my '98 XJ Sport (4 ltr, auto) has been draining the battery when it sits over 2 hours (battery is 2 weeks old - and yes, it's a good battery).

I put my ammeter in series with the negative battery post/cable, and made sure that all the doors were closed, engine bay light was off, etc.

The constant drain on the battery is 5.75 Amps!!!

Well, no wonder my battery is dying!

So I pulled every fuse (under the hood and interior kick plate) - the Amp draw never went under 5.7.

So what am I overlooking? What else do I need to check? --I even pulled all the relays!

I am at a loss, and this is my daily driver - I need to fix this ASAP!

Any suggestions??

The positive battery cables go to the PCM, starter and indirectly from the alternator...

Disconnect the ground, remove the positive cable that goes to the starter and then read from the battery ground to the ground cable.
Do the same for the positive cable going to the PCM and alternator....
This should help you further narrow down where the draw is coming from...

OK, so it's not the PCM or starter... can't get my hand in the right place to remove alt wire - surely I don't have to remove the air cond compressor to get to it, do I?

Anyway, removed starter, PCM, and PDC wires. Drain went away when I removed the PDC wires, so I went through again and removed each fuse and relay individually (inside and out) with absolutely no change...

Thoughts, anyone?

Also, say I get completely fed up with this and put on a battery switch... aside from the computer resetting, no power locks, and no presets on the radio... any other issues with this?

I'm about sick of dealing with this.

Thanks for the help!

How about the big relays under the hood? I wonder if you have a sticky one. Also there is a group of big fuses under the hood, have you pulled those?

Yeah, pulled everything in the PDC, including all relays...

Ok, sorry PDC means Primary Domain Controller to me

Yeah... I meant Power Distribution Center...

If you haven't already done so look for a diagram on the PDC. Make sure there isn't something hidden from view that you are missing. Unless the PDC box itself is bad, but I would think at 5 amps something would be smoking.

Haven't found a diagram yet, but that was exactly what I was thinking... at 5 -- almost 6 amps, you'd think I'd hear, see, or smell something!!

Anybody ever hear of the PDC going bad?

This isn't a diagram but it might be helpful.

::<image from FSM removed from post>::

This is from a 2000 XJ model, I have not verified it against my 98.

OPERATION
The term ignition-off draw identifies a normal condition
where power is being drained from the battery
with the ignition switch in the Off position. The IOD
fuse feeds the memory and sleep mode functions for
many of the electronic modules in the vehicle as well
as various other accessories that require battery current
when the ignition switch is in the Off position,
including the clock. The only reason the IOD fuse is
removed is to reduce the normal IOD of the vehicle
electrical system during new vehicle transportation
and pre-delivery storage to reduce battery depletion,
while still allowing vehicle operation so that the
vehicle can be loaded, unloaded and moved as needed
by both vehicle transportation company and dealer
personnel.
The IOD fuse is removed from PDC fuse cavity 16
when the vehicle is shipped from the assembly plant.
Dealer personnel must install the IOD fuse when the
vehicle is being prepared for delivery in order to
restore full electrical system operation. Once the
vehicle is prepared for delivery, the IOD function of
this fuse becomes transparent and the fuse that has
been assigned the IOD designation becomes only
another Fused B(+) circuit fuse. The IOD fuse serves
no useful purpose to the dealer technician in the service
or diagnosis of any vehicle system or condition,
other than the same purpose as that of any other
standard circuit protection device.
The IOD fuse can be used by the vehicle owner as
a convenient means of reducing battery depletion
when a vehicle is to be stored for periods not to
exceed about thirty days. However, it must be
remembered that removing the IOD fuse will not
eliminate IOD, but only reduce this normal condition.

Yeah, looks just like mine. The B+ referred to above is where I disconnected to make the amp draw stop...

...and I think I'm going to remove the IOD fuse to see if that helps any overnight tonite...

Thanks, I'll post tomorrow with results. I'm fixing to run out and see if it will start (hasn't been started in a couple of hours). If it does, I'm going to try for the first time in about a week to let it sit overnight without a trickle charger on it.

Had a simalar poblem with my 88 XJ. Turned out to be if I left the vent on and thefan switch in ANY position other than off the the fan would run even if I couldnt hear it running went I exited the car (who would "listen" for things running when one turns off the ignition switch and leaves the car?)

Dont know why but now when I exit I make sure my fan is off.

Funny thing... I just thought about that when I went to the garage to check on it... the only day this week that it started after work with no problems (didn't even go to lunch that day), it was a very mild day, and I think I had the air/vents off, so I turned it off. We'll see...

have you hooked up any switches lately???

t-frady said:

have you hooked up any switches lately???

Click to expand...

Nope, actually, haven't done a thing to the Jeep in about 3 months, which is rare... maybe she's just feeling neglected!

OK, now I'm totally confused. Go out this AM - put the multimeter on the battery - 12.70 Volts.

Disconnect the neg cable - still showing 5.7 or so amps draw.

Get in, and she fires right up - no hesitation .

Don't know what to do at this point.

I seriously am considering running a 1 ga wire into the cab, hooking up a batt switch, and running the 1 ga back out to the battery!

I can't find the source, and I cant even get it to "not start" while it's showing the drain for a whole night!!

I hate electrical problems!!

Have you tried removing the alternated lead, then testing it?

What about the radio, cb, or maybe light bulb that's blown??

E

jmowens said:

Nope, actually, haven't done a thing to the Jeep in about 3 months, which is rare... maybe she's just feeling neglected!

OK, now I'm totally confused. Go out this AM - put the multimeter on the battery - 12.70 Volts.

Disconnect the neg cable - still showing 5.7 or so amps draw.

Get in, and she fires right up - no hesitation .

Don't know what to do at this point.

I seriously am considering running a 1 ga wire into the cab, hooking up a batt switch, and running the 1 ga back out to the battery!

I can't find the source, and I cant even get it to "not start" while it's showing the drain for a whole night!!

I hate electrical problems!!

Click to expand...

I really don't think you could have a 5.7 amp draw for hours and have your Jeep start right up. It might be time to verify what you are reading from your meter.

Mudderoy said:

I really don't think you could have a 5.7 amp draw for hours and have your Jeep start right up. It might be time to verify what you are reading from your meter.

Click to expand...

I was thinking the same thing...

It's my father-in-law's multimeter, but I'm pretty sure it's set up correctly - I have it on the setting for DCA, and the black lead in the 10A hole, with the red one in the "red" hole. I am disconnecting the neg batt cable and placing the multimeter in series (in line) with the cable and neg battery post... This is the right way, right?

I'm at a loss...

jmowens said:

I was thinking the same thing...

It's my father-in-law's multimeter, but I'm pretty sure it's set up correctly - I have it on the setting for DCA, and the black lead in the 10A hole, with the red one in the "red" hole. I am disconnecting the neg batt cable and placing the multimeter in series (in line) with the cable and neg battery post... This is the right way, right?

I'm at a loss...

Click to expand...

I haven't read amps on anything in YEARS. I'd have to go back and review the steps. What I remember is that the meter MUST be capable of the amperage you are going to run through it. You put the meter in the position to measure current, proper lead hole. Place the meter in the circuit. I would use the positive side, but I can't think of a reason the negative side wouldn't work. Adjust range to get reading.

Maybe you are doing it all correctly with the exception of reading the value correctly. Perhaps it is .57 amps? Which would still be about 4 times higher than what it should be (if I am remembering correctly).