I have a 1998 Grand Cherokee 4 X $ which has been draining the battery. Today I spent the afternoon trying to find the source of my current drain. Removing the negative ground cable from the battery I had 190 ma drain, Finally narrowed it down to the instrument panel fuse, after removing I am down to the 20 ma normal drain.
I removed the instrument cluster, light switches, rear wiper switch, and all connections to the PCM. I still had the 190 ma drain. Only by removing the fuse can I get it to normal.
Does anyone have a more detailed wiring diagram then the Haynes version? Any other thoughts on circuits tied in to the instrument cluster that could have this sort of drain. Keep in mind thatnot any other fuse in either box removed the drain.
Fuse #7 is the fuse I have it traced to. Having completely disconnected the PCM and cluster, and not haveing the sensing headlights or LED alarm indicator, looks like I'll be checking the amplifier circuit when I get home tomight...
Just for clarification I had not checked this connection or even thought of it. What does the BCM control?
The BCM controls the Intermittent wipers, Interior lamp relay, Panel lamp dimming, Stores and displays odometer mileage, operates digital Vehicle info display (if equipped), controls theft alarm and auto headlamps (if equipped), rear window defogger, various warning lights, chime, fog lamps, and transmits the A/C compressor signal to the PCM.
The bcm is behind the knee blocker under the steering column, to the left. It has one plug that points down, towards the floor. and 2 plugs that point forward, towards the engine compartment.
My guess is you will probably find your trouble at the amp.
Just pulled the plugs o the BCM and my current draw drops. The white plug in the back closet to the door is the culprit. When this on and only this one is unplugged my current draw drops to the 20 mz expected. If anyone has a wiring diagram and can tell me the circuits in this plug I would appreciate it.
Is it possible the BCM is bad. Does this need to be replaced by a dealer or can I put in a used one?
Ambient Light sensor*
Steering wheel radio control sense*
Wiper motor park sense
A/C select input
Courtesy lamp relay control
Auto headlamp relay control*
Horn relay control
Defogger relay control
Panel lamp driver
Panel lamp dimmer switch signal
Washer switch output
Wiper Switch sense
Park lamp relay control*
Fog lamp relay control*
Intermittent wiper relay control
Just curious, when you are doing these tests, are any of the doors open? If so, the BCM will activate the courtesy lamp relay, and even with the relay or fuse removed, this will cause an elevated drain. If so, plug the bcm back in, replace the fuse, then close all doors, wait ~30 seconds, and re-test the drain.
Thanks for all the help. I have been shutting the doors after every disconnect and waiting before measuring the current. After removing combinations of the plugs have determined that it is definitely the white plug into the BCM that is the culprit. I removed the steering whell covers and unplugged the wiper control plug so feel like I have eliinated several of the wires from this plug. I don't have any of the options listed so the list is getting pretty narrow. I close to buying a new BCM off of ebay and see what that does.
I appreciate all the help I have gotton and as much as I love my Jeep I am very frustrated trying to track this little demon down.
Did you try unplugging the other plugs for the BCM while leaving the white connector plugged in? The drain could be on another circuit downstream of the BCM, and it just stops when you cut the power supply to the BCM.
Also, try unplugging the wiper motor, the Intermittent Wiper relay, the headlamp switch, and the defogger switch (witht he BCM plugged in) to see if that lowers the drain.
It's been a few weeks and I have my problem fixed. Thanks for all the help and wanted to share what the problem was. Finally took the Jeep into an auto electric repair shop. Turned out the BCM thought the rear hatch window was open, making the BCM want to turn on the Driver Information display to indicate the hatch was open. However, disconnecting the switch didn't solve the problem as they said the BCM still wanted to turn on the display. The problem turned out to be the display, which had a defective circuit and only after disconnecting the display did the drain stop. I had only the basic display indicating open doors and whether I was in two or four wheel drive, so having to look at the Selectrac instead of the display is no big deal. Simple problem but what a pan to find. I can say the shop was nice and took into account my diagnosis up to where I gave up and only charged me 2.0 hours of labor for their effort.