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Unread 03-01-2011, 12:29 PM   #1
Briggy
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1994 YJ Wrangler 
 
Join Date: Feb 2011
Location: Bay shore, Ny
Posts: 4
Possible bad bcm?

My buddys zj is having multiple issues, all happen at the same time. Delay wipers don't work, power windows don't work, rear wiper doesnt work, and the dashboard display dims out. Disconnected the battery for a few minutes then reconnected and everything works, then died again. Bad body control module???

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Unread 03-01-2011, 05:47 PM   #2
tomk864
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1999 TJ Wrangler 
 
Join Date: Dec 2005
Location: San Jose, CA
Posts: 171
Check all grounds.
Mine was having all kinds of problems: instrument cluster very erratic, windows spontaneously going down, VIC resetting.
There's a ground connection on top of/next to the alternator that was loose.
Not completely sure it's cured, but very hopeful.
This is on a 96 ZJ, 5.2L.

There are also 2 grounds from the battery: one to engine block one to fender.

tomk

(For what it's worth, I believe the loose ground I had was causing the PCM to overcook the alternator, resulting in (intermittent) voltages as high as 20 volts. I really wish the voltage regulator wasn't built into the PCM.)
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Unread 03-01-2011, 06:09 PM   #3
98mopar
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1998 ZJ 
 
Join Date: Feb 2011
Location: desoto, kansas
Posts: 262
Kind of sounds like you have a short some where in the harness. Does your buddy have a stereo? Seems like if your disconnect the batt. and reconnect it, and it all works for a short amount of time. Something is overloading the circuit. Do these same problem happen if your engine is off?
I would definitely check all grounds first.
I would also check your connection at your ecu. I noticed on my 5.9 and on another 5.2 those connections get corrosion on them.
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Unread 03-02-2011, 05:08 AM   #4
Briggy
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1994 YJ Wrangler 
 
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Location: Bay shore, Ny
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No stereo, just factory. Doesn't matter engine on or off. Will double check all the grounds, but disconnecting the battery then it works makes me think it's not just a wire...
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Unread 03-02-2011, 07:42 AM   #5
JS97ZJ
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1997 ZJ 
 
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Location: Dingmans Ferry, PA
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What yr ZJ? When you disco the battery, does the problem resurface by itself or when you open or start operating certain things? (radio, windows, open doors etc.)
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Unread 03-02-2011, 09:36 AM   #6
98mopar
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1998 ZJ 
 
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I am still thinking you have a short, these jeeps have very very bad insulation on there wiring and it gets hard and cracks and breaks and exposes the wires.
How many times have you tried disconnecting the batt and hooking it back up? Is it always the same amount of time till it cuts out? How long is it after you hook it back up till it goes bad again?
You may want to try, pulling fuses for individual components. Like pull your power window fuse, and see if you still have other problems, and continue that process and try to single out the problem area.
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Unread 07-27-2011, 09:28 PM   #7
RiverCityWK
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2005 WK 
 
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Location: Richmond, VA
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Sorry to resurface an old topic but I'm having some issues in my 97 ZJ that I believe are tracing back to my BCM. I was working on some last touch wiring on my aftermarket 4 channel amplifier when I heard a pop like a fuse blowing. When I pulled the amp up, I noticed that my ground had come a loose. At first I though maybe I blew a fuse but all of the fuses/relays check out. Now I have no instrument cluster functions with the exception of the signal lamps and the lights as well as no power windows or locks from the door panel although the power locks function with the key fob. I swapped in a used BCM from the junkyard and I'm still having the same issues. I called the dealership and they said my ZJ won't recognize another BCM until it's flashed. Does this sound right, or am I trying to fix the wrong thing?
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Unread 07-27-2011, 09:37 PM   #8
breeaad
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Quote:
Originally Posted by RiverCityWK View Post
Sorry to resurface an old topic but I'm having some issues in my 97 ZJ that I believe are tracing back to my BCM. I was working on some last touch wiring on my aftermarket 4 channel amplifier when I heard a pop like a fuse blowing. When I pulled the amp up, I noticed that my ground had come a loose. At first I though maybe I blew a fuse but all of the fuses/relays check out. Now I have no instrument cluster functions with the exception of the signal lamps and the lights as well as no power windows or locks from the door panel although the power locks function with the key fob. I swapped in a used BCM from the junkyard and I'm still having the same issues. I called the dealership and they said my ZJ won't recognize another BCM until it's flashed. Does this sound right, or am I trying to fix the wrong thing?
Does it start with the junk yard bcm? If so, it doesn't need to be flashed. I have a 98 gc, and I once researched it and found that NFL did not have to carry the vin until 99 model. But if it has to be flashed, then the security system won't allow it to start.
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Unread 07-27-2011, 09:39 PM   #9
breeaad
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Quote:
Originally Posted by breeaad View Post
Does it start with the junk yard bcm? If so, it doesn't need to be flashed. I have a 98 gc, and I once researched it and found that NFL did not have to carry the vin until 99 model. But if it has to be flashed, then the security system won't allow it to start.
NFL means bcm. Stupid autocorrect
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Unread 07-27-2011, 10:16 PM   #10
RiverCityWK
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It starts just fine
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Unread 07-27-2011, 10:21 PM   #11
RiverCityWK
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Should I be looking elsewhere?
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