Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn LW200, 2002 Saturn L200, and 2002 Saturn L100. However, it is still accessible from the selected car via links, so may be relevant.
To locate an intermittent problem, use Scan tool to monitor CRUISE BRAKE/CLUTCH SW with brake pedal depressed while wiggling wires. The scan tool will read RELEASED when no voltage is present at the PCM brake switch input. Wiggling wires while watching for a change from APPLIED to RELEASED may locate the area where an open or short to ground in the wiring could lie.
The stoplight switch should have under 2 ohms resistance across its terminals when the plunger is all the way out.