System Diagnosis

SYSTEM DIAGNOSIS
Diagnosis for this system is based on diagnostic codes stored in the Heater and A/C Control Assembly. When a code has been stored the EXT TEMP indicator on the assembly will flash.

To enter the Diagnostic Mode and read the code, press and hold the EXT TEMP button while pressing and releasing the AUTO button. A mode number will appear in the display. The diagnostic mode is Mode -08. Advance the display to -08 by repeatedly pressing the WARM button. The diagnostic code may now be displayed by pressing the COOL button. Note: there are modes other than 08, but they are not normally useful for service.

If a single code is stored, it will be one of those listed in the Symptom Table following. If more than one code is stored, the number will represent the sum of the two codes. For example, if codes 02 "Outside Temperature Sensor Open" and 08 "In Car Temperature Sensor Open" both are stored and the code displayed would be 10 (02 + 08 = 10).

Once you have determined which code is set, perform the diagnostic tests for the code or symptom in the Symptom Table. Check for additional diagnostic codes after making any repairs.