I need to know where the Body Control Module is located on a 2000 Cadillac Catera,

BCM Replacement
Replace the BCM only if diagnostics in this section directs you specifically to do so. Most system problems are traceable to faulty wiring, to connectors, or to components. The BCM itself is very reliable and is not likely the cause of a fault. Do not replace the BCM before performing a complete diagnosis or recurrence of the fault will likely occur. Note: Every input to the BCM is short to ground and short to battery protected. Every output from the BCM is short to ground and short to battery protected. Therefore, the BCM does not automatically need to be replaced when there is a short found in the wiring connected to it. Repair the wiring first, then check the system for any further problem.

BCM Programming
When a BCM is replaced, it must be programmed with the Vehicle Identification Number (VIN) of the vehicle that it is being installed in. The RadioTheftlock feature uses the VIN to verify that the radio has not been removed and improperly installed in another vehicle.
The programming of the BCM is accomplished by using a scan tool. The vehicles VIN is entered in the scan tool and then transmitted via a Class 2 physical message to the BCM. The BCM stores the VIN in EEPROM. The first communication between the BCM and radio re-arms the Radio Theftlock. To set up a new BCM, select SETUP NEW BCM from the BCM Special Functions menu and follow the instructions on the screen.

Body Control Module (BCM)
Mounted on the RH Kick Pad, behind the trim panel