Chevrolet Repair: 98 gmc jimmy, powertrain control module, powertrain control module pcm

Question
I have a gmc jimmy with what may be an electrical prob. Some time ago my rear wiper stopped working. It comes in and out of the cradle, but won't wipe. A few weeks ago, I noticed the power mirrors only move in one direction. Recently, the 4WD selector would not go into 4 HI, but would go into 4LO and 2HI. 2 days ago, the power seat stopped working, but then a few minutes later it started working again. I disconnected the battery for a few seconds, which seemed to reset the 4WD problem (however temporary) but nothing else is resolved. A friend told me that it may be the body control module. It that true, and where is it located? Thanks

Answer
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 vehicle 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.

It doesn't take but a few minutes to put it in and if it doesn't fix the problem, then just take it out.

I assume that you checked all the fuses, but I would be remiss if I didn't mention this. There might be  IOD fuse in the fuse box. If it is blown, you will have the same symptoms.
as for location, talk toa mechanic or dealer, but for what i can find, its a huge harness type block under the dash, by or near the gas pedal.