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Discussion Starter · #1 ·
My son has a 1998 5.9 Grand Cherokee Limited and after being parked for a week and a half the battery is so weak that it will not start. We have put in a new battery but it still happens. The specs say that ignition off draw should be 5-30 milliamps. We have tested Ignition off draw current and it reads 75 milliamps. We have disconnected the alternator and no difference. We seem to have traced it to 3 circuits. But not sure which one of these circuits is the problem. These are the underhood fuses.
The IOD 40 amp circuit takes about 20 milliamps
The IGN feed 40 amp circuit takes about 20 milliamps
The MUX/TOW 50 amp circuit takes about 40 milliamps.
Are any of these normal?
This Jeep also has a Rattler remote starter that I know nothing about with what seems to be 4 fuses under the drivers side dash, removing these fuses makes no difference but am not sure if it has fuses anywhere else.
Looking for any advice,
Thanks,
Mike
 

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I would also check simple **** like the under hood light, door switches including the hatch.
But if you deff. have it pegged to the listed circuits than I would start with the IGN feed simply based on the bundle of wires under constant movement in the steering column especialy with tilt wheel, on the other hand did you kinda wiggle the conections around on the bottom of the under hood fuse box while doing your draw test ? and where the wires go through the firewall, Relay within those ciruits,

I went through something like this (and still do) with my ZJ, but mine seems to act like a short across a diode someplace and I'm led to beleive that it's in my BCM,I don't hav a batt issue but I have an issue of my dome light fuse blowing when it "times out" after my alarm is set, I have normal draw on the batt. but a quick burst of current on just my dome lights at alarm "time out".
I'm an elec. tech and myself and our engineer at work can't really figure it out, and really never had time to go into anymore depth of troubleshooting.
 

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I just did some quick looking at my JEEP and that MUX/TOW runs to fuse #7 inside the jeep which is for a few things with one of them being the BCM
 

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keep us updated. The jeep I just bought had a dead Yellow top. I also have a friend whos jeep has killed a handfull of Red tops. I never really thought much of it but I'd hate to have to deal with an illusive electrical draw.

Being as handy with electrical stuff as a screen door in a submarine, would a battery cut off switch help?? or maybe some sort of toggle switch on the problem circuits ??

Unfortunately I'm clueless with this particular stuff ... don't hate me :shhh:
 

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I'd almost wonder if it was a chaffed wire that's always hot. It may have the insulation just skinned up enough that it slowly draws off power.
 

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Discussion Starter · #6 ·
update

OK finally had some time to make some more checks. This time we went inside and pulled the fuses in that fusebox. The only fuses that affected the current draw are:
Fuse 7 Cluster 15ma difference
Fuse 8 Flip soln about 3 ma
Fuse 20 Rad/hvac 15ma difference
So I think I'm back to square 1.
Since fuse 7 is only pulling about 15ma does this rule out the BCM?
Still wondering if any of the measurements I took pulling fuses from the box under the hood are normal so that I'm not chasing something that is OK.
Tried the hood light, rear hatch, glove box light and anything else we could think of.
I don't have an actual wiring diagram for the Jeep all I have is The Haynes Repair Manual for Jeep Grand Cherokee 1993-2004 which is a general kind of thing.
I would prefer to stay away from a battery cutoff switch because I think this will bring the Jeep back to ground zero and it would have to be driven a hundred miles or so to bring the comp back to where it should be.
 

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Two other guys I helped out with this problem it turned out to be that the BCM was not going into sleep mode after the delayed courtesy lites in fact turned off.
It turned out to be the lift gate ajar switch was screwed up. Take the hatch panel off and disconnect the p/j connector. Having the connector apart will make the BCM think every thing is A-OK then it should go to sleep. The door interlocks work the same way.
The BCM monitors all the interior functions and if you have the limited package, you'll have the temp. control, memory seats, plus all the other convenience crap that might be a drag on the system if something other the hatch or doors is not the problem.
 

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Two other guys I helped out with this problem it turned out to be that the BCM was not going into sleep mode after the delayed courtesy lites in fact turned off.
It turned out to be the lift gate ajar switch was screwed up. Take the hatch panel off and disconnect the p/j connector. Having the connector apart will make the BCM think every thing is A-OK then it should go to sleep. The door interlocks work the same way.
The BCM monitors all the interior functions and if you have the limited package, you'll have the temp. control, memory seats, plus all the other convenience crap that might be a drag on the system if something other the hatch or doors is not the problem.
ditto^^^

This is very possible, correct me if i'm wrong but............
you could turn the key to on during your draw test than back off and in roughly 30 sec you should see a drop in Ma when the BCM goes into sleep mode, if no drop than that is your issue................

does this sound feesable ?
 

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Discussion Starter · #9 ·
After turning the key on then off and also opening a door and closing it it seems to get to the final 85ma draw it goes down to in I think 3 or 4 steps before it levels out at 85ma. It pull some current, not sure didn't check it then after oh I'd say a minute or so it goes down to pulling over 250ma then after about a minute or so it goes down to about 150ma then after about another minute it falls to 85ma
 

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It takes at least 3 min for everyone to fall asleep. When you open a door, everyone wakes up again untill door is closed. You have to play the waiting game. If you have over 0.030 amps after 3 min and you narrowed it down to a specific fuse, plug it back in and start unplugging everything that fuse powers. As mentioned, BCM's are sometimes the culprit. Hope this helps. good luck.
 

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Can the BCM be replaced or reprogrammed?
replaced,
or take it apart and see if you can see the issue, I had an open trace in my prev. BCM and was able to fix it (alarm issue),
make sure you are ESD safe before opening the BCM.

I have seen them on ebay for $60 or so.
 

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Discussion Starter · #13 ·
confused

I'm confused here, no one really has answered my original question which was are any of the current readings from under the hood normal? Then I will know which fused circuit (IOD or IGN feed or MUX/TOW ) to dig into.

We have put in a new battery but it still happens. The specs say that ignition off draw should be 5-30 milliamps. We have tested Ignition off draw current and it reads 75 milliamps. We have disconnected the alternator and no difference. We seem to have traced it to 3 circuits. But not sure which one of these circuits is the problem. These are the underhood fuses.
The IOD 40 amp circuit takes about 20 milliamps
The IGN feed 40 amp circuit takes about 20 milliamps
The MUX/TOW 50 amp circuit takes about 40 milliamps.
Are any of these normal?

Then we went inside and pulled the fuses in that fusebox. The only fuses that affected the current draw are:
Fuse 7 Cluster 15ma difference
Fuse 8 Flip soln about 3 ma
Fuse 20 Rad/hvac 15ma difference

So if fuse #7 is only pulling 15ma then am I correct in assuming the BCM is OK?
Should IGN Feed and IOD be consuming any current? Or should IGN feed and IOD be consuming some current but not the MUX/TOW circuit? And does anyone know what MUX/Tow should consume with fuse 7 pulled?
Sorry about this I'm just trying to nail it down some so I'm not chasing my tail too much, but I also want to thank everyone for taking the time to respond with their ideas and thoughts because they also got me looking at other things.
 

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I know this is an old thread but hopefully someone can shed some light into this.

I have been diagnosing battery drain problem on my new (for me) 2002 Jeep Grand Cherokee Limited.
It drains a new battery in about 1,5 days.

I finally got a meter with 10A range to display.

Turns out that the car is drawing about 1.7A with the key off and after resting for about 45min.

Question 1: What would be the normal expected draw on Jeep? SOme sources say in general it should be 25mA to 40mA or so.

I've tested all fuses under the hood and no change.
I tested also the Junction Block fuses 1-33 and no other changes than when I pulled both F28 and F30, the draw dropped to 0.33A which still should be way to much.

Question 2: Does this indicate anything that seems typical for any one of you here?

Schematics show that there are relays etc. near the fuse panel. Would it be worth doing the sale for the relays etc. I suppose...

F28 seems to be the BCM which I gues could be a culprit and connected to many different places in the vehicle.

Is there any other suggestion what I should be looking up??

Cheers,
Jani
 

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This thread is about a ZJ (93-98 Grand Cherokee) which has a very different electrical system from your WJ (99-04 Grand Cherokee).

You will get better help for you WJ (1999-2004 Grand Cherokee) by posting in the forum for that model: http://www.jeepforum.com/forum/f310/
 

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I'm confused here, no one really has answered my original question which was are any of the current readings from under the hood normal? Then I will know which fused circuit (IOD or IGN feed or MUX/TOW ) to dig into.

We have put in a new battery but it still happens. The specs say that ignition off draw should be 5-30 milliamps. We have tested Ignition off draw current and it reads 75 milliamps. We have disconnected the alternator and no difference. We seem to have traced it to 3 circuits. But not sure which one of these circuits is the problem. These are the underhood fuses.
The IOD 40 amp circuit takes about 20 milliamps
The IGN feed 40 amp circuit takes about 20 milliamps
The MUX/TOW 50 amp circuit takes about 40 milliamps.
Are any of these normal?

Then we went inside and pulled the fuses in that fusebox. The only fuses that affected the current draw are:
Fuse 7 Cluster 15ma difference
Fuse 8 Flip soln about 3 ma
Fuse 20 Rad/hvac 15ma difference

So if fuse #7 is only pulling 15ma then am I correct in assuming the BCM is OK?
Should IGN Feed and IOD be consuming any current? Or should IGN feed and IOD be consuming some current but not the MUX/TOW circuit? And does anyone know what MUX/Tow should consume with fuse 7 pulled?
Sorry about this I'm just trying to nail it down some so I'm not chasing my tail too much, but I also want to thank everyone for taking the time to respond with their ideas and thoughts because they also got me looking at other things.
Did you ever get this resolved. I have the exact issue with a 1998 Grand Cherokee
 
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