Bad BCM OR Electrical problem?

If I am ever asked for a site to use to diagnose a problem with a gm car or truck, this site will come highly recommended!

How can I be sure the BCM is Bad? I don't have Fuel cluster working and the Climate control doesn't work, all fuses are good, there is no lights on the gauges at all, so the codes dont show up. Thanks Dodge

The passenger side door will lose power sometimes, meaning none of the power windows, power locks or heat seat buttons work. None of them illuminate either if headlights are on. You also can not power down the window by using the driver's side buttons, nor the power locks. This seems to last for a little while, then they magically start working again as if nothing is wrong. I am told it might be the BCM, Where is that located on the car?

Where is the body control module located at on this car?

I have had to replace the head gasket on this car and several things were replaced while it was apart. Now something is keeping the accessories running and it the battery is dead when we go to start it. Any ideas short of getting rid of the car? We put on new battery in it in November and it is a Delco. Since then, on occasion the security alarm will go off on this car also.