Ignition Coil Power Source
WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 1991 Pontiac Sunbird, 1991 Pontiac Grand Prix, 1991 Pontiac Grand Am, 1991 Pontiac Firebird, and 1991 Pontiac Bonneville. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition on and check Pink or Pink/Black wire of ignition module for battery voltage. If battery voltage is not present, check ignition or ECM fuse. If fuse is not blown, check for open between fuse and ignition module.