Initial Inspection and Diagnostic Overview

The control assembly (head) detects certain system faults during normal operation and is capable of testing for other faults during the ``self-test.'' If an actuator malfunction is detected during normal operation, the Vacuum Fluorescent Display (VFD) or mode Light Emitting Diode (LED) will blink.
When a malfunction is detected, the error code(s) may be displayed by simultaneously depressing the Off/Auto and Defrost buttons, then the A/C button within two seconds to initiate the ``self-test.'' Error codes found during the ``self-test'' will be displayed along with any faults found during normal operation. Activation of the ``self-test'' will stop normal operation of the system. To exit the ``self-test'' and restart the system, the Cool button must be depressed.
Refer to error code key, and pinpoint tests A through G, to diagnose any displayed error codes. If a malfunction exists, but no error code is displayed, refer to pinpoint tests H through P. Displayed error codes must be considered invalid if in-vehicle temperature is 50 F or less.