A/C-Heater Programmer (ACM) Self-Diagnostics: Notes
WARNING: This page is about a different car, the 1998 Cadillac Eldorado and 1998 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Operating vehicle in self-diagnostic mode for extended period without engine running will drain battery, possibly causing system to give false diagnostic information. If vehicle is in self-diagnostic mode for more than 30 minutes, connect charger to battery.