Further unplugging of devices has targeted the issue to the Right Rear Lamp Assembly. I eliminate the symptom of the "ignition bypass" if I unplug the rear lamp. That harness is a 6 pin connector that goes to 1. Ground, 2. Headlamp switch output, 3. Right turn signal output, 4. Brake lamp relay output, 5. Backup lamp switch output, 6. n/a.

When I perform the right tail lamp inoperative tests the vehicle passes. When I complete the right stop lamp inoperative tests I get continuity from the ICM to connector 4. Testing voltage at connector 4 to ground with the brake applied should produce voltage and it does not. The connection from pin 1 to ground is good.

The repair manual suggests replacing the ICM and performing the test again. I still get the same result with the new ICM.

This is starting to look like a bad relay, since the relay output is the pin causing the issue. This is weird. My car is posessed.