The connections to be made on the Grand Prix are at the Body Control Module. The Body Control Module is under the dash, left side by the parking brake pedal.
Remove the left instrument panel insulator. Refer to Instrument Panel Insulator.
Disconnect the BCM electrical connectors.

There are only 2 connectors. First is the nature or white C1 with 8 terminals.

And second is the Blue C2 connector with 32 terminals.

These pictures are looking into the end of the plug that goes into the module.