1. Simultaneously press and hold AUTO and recirculated air buttons. See Fig. 1. Turn ignition on. All indicators will flash 4 times, at one-second intervals. A tone will sound when indicators flash. To cancel indicator check, press OFF button.
2. After indicator check is complete, system will enter self-diagnostic mode. Stored trouble codes will appear in sequence on driver side temperature display.
3. To slow rate at which codes are displayed, press passenger side TEMP (up arrow) switch to change display to step operation. Each time TEMP (up arrow) switch is pressed, display changes by one step.
4. If tone sounds as a code is displayed, problem currently exists. If tone does not sound as code is displayed, problem does not currently exist (history code). To exit self-diagnostics, press OFF button.