System Diagnostics

There are twelve diagnostic modes as described below. Diagnostic mode number 8 is the most commonly used mode for diagnosing the system. The diagnostic mode is entered while pressing the "EXT TEMP" button and then pressing and releasing the "AUTO FAN" button. Once the diagnostic mode is enabled, the mode number may be changed by pressing the "WARM" button. The contents of the mode may be displayed by pressing the "COOL" button. The mode number is displayed preceded by a minus sign.

^ Mode # 1 - Program Number
^ Mode # 2 - In-Vehicle Thermistor
^ Mode # 3 - Ambient Correction
^ Mode # 4 - Blower Number
^ Mode # 5 - Outside Temp Thermistor
^ Mode # 6 - Feedback Pot Position
^ Mode # 7 - Calculated Door Position
^ Mode # 8 - System Faults
^ Mode # 9 - Radiometric Feedback Position
^ Mode # 10 - Full Hot Position
^ Mode # 11 - Full Cold Position
^ Mode # 12 - Software Version Number

System Faults - A system fault is indicated by a flashing indicator. If there is a problem with the ambient sensor, in-vehicle sensor, or the feedback potentiometer, the EXT TEMP indicator will flash for approximately 60 seconds, upon ignition "ON." The flashing indicator will reoccur upon ignition "ON" until the system problem has been corrected. To further investigate a system problem, a diagnostic data word can be examined. The diagnostic data word is displayed by entering diagnostic Mode #8. The diagnostic data word is a number that indicates the failure mode. Faults can be determined by evaluating the binary equivalent of the diagnostic data word displayed. A "1" in a column is an indication of an error of that category. The diagnostic mode can be exited by depressing any mode button on the ECC control face.