Ignition Coil Power Source
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1990 Pontiac Sunbird, 1990 Pontiac Grand Prix, 1990 Pontiac Grand Am, 1990 Pontiac Firebird, and 1990 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/ECM fuse. If fuse is not blown, check for open between fuse and ignition module.