Questions and Answers
Caravan Body Control Module
Q. I recently had to replace my second battery on my 1998 Dodge Caravan (I've had it four years, 91,000 miles). I had a few quirky things happen prior to then, such as the A/C not blowing properly, interior dash lights not coming on with the headlights, and radio stations resetting.
However, since the battery replace, I lost headlights and dash lights completely, as well as all interior lights. The interior lights do come on occasionally, but sometimes the switch works opposite of how it's supposed to. I took it to a dealer already for diagnostics, and they said I probably need the BCM replaced.
This is a rather pricey fix, and I understand that this is not a common problem. In fact the technician was only about 90% sure that replacing the BCM would fix the problem. Does this seem like a reasonable solution to my problem? No wiring or fuses seem to be involved, as they can get the lights to flash, but not stay on. Is it likely that this occurring with the failed battery is just coincidental, or am I barking up the wrong expensive tree?
Thank you for any help or suggestions.
HeidiA. Okay Heidi, this is what the Body Control Module does:
The Body Control Module (BCM) supplies vehicle occupants with visual and audible information and controls various vehicle functions, To provide and receive information, the module is interfaced to the vehicle's serial bus communications network, the Chrysler Collision Detection (CCD) bus. This network consists of the powertrain control module (PCM), the Transmission Control Module (TCM) , the electro/mechanical instrument cluster (MIC) , the Airbag Control Module (ACM) , the Compass/mini-trip module and the Controller Antilock brake Module (CAB). The BCM is operational when battery power is supplied to the module. Ignition switch power is needed for ignition switch functions.
The BCM provides the following features:
• Automatic door locks
• Battery protection
• Chimes
• Compass/mini-trip support
• Courtesy lamps
• BCM diagnostic support
• Door lock inhibit
• Headlamp time delay
• Ignition key lamp
• Illuminated entry
• Instrument panel dimming
• Mechanical instrument cluster support
• Power door locks (with/without remote keyless entry)
• Sliding door memory lock
• Vehicle Theft Security system (VTSS)
• Windshield wipers / washers (front and rear)As you can see, it is central to the control systems of the van and can be very complex. To my way of thinking if one or maybe two systems connected to the BCM have a problem, then the cause is probably within that system. But when they all have a problem, then I have to think the BCN is bad.
At the very least they can try it. It doesn't take but a few minutes to put it in and if it doesn't fix the problem, then can just take it out.
I assume that they checked all the fuses, but I would be remiss if I didn't mention this. There is a IOD fuse in the fuse box. If it is blown, you will have the same symptoms. And since it is possible for a fuse to pop while replacing a battery, I think that ALL the fuses should be checked with a meter and not just visually.
Additional Information provided courtesy of ALLDATA