Air Conditioning/Climate Control

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Climate Control Diagnostics

This information was taken from a Skyline forum and will be changed at a later date.

The climate Control has a diagnostic mode.

Enter the diagnostic mode by pressing the OFF button for five seconds within ten seconds of turning the ignition on.

Sensor check

Sensor check is selected by pressing HOT switch (the red triangle) while in diagnostic mode. The microcomputer detects whether each sensor input signal is within correct parameters. The results are displayed on the screen.

If normal, a "20" is displayed.

If abnormal the failed sensor number is displayed. The sensor numbers are as follows:

20 - all is normal

21 - outside air sensor

22 - Inside air sensor

23 - Water temperature sensor

24 - Intake temperature sensor

25 - Sunload sensor (small sensor on the left hand side of the dashboard near the windscreen)

26 - PBR

27 - Refrigerant temperature sensor

This should tell you if any of your sensors are faulty.

Mode door position check

(This is probably not the cause of your problems but it is a nifty self check to play with). While in Sensor check, depress the HOT button again. This will operate the the mode door actuator, and checks the whether the position detection switch is operating. Again the results are displayed on the display.

If normal, a "30" is displayed.

If abnormal the number of the faulty mode is displayed as follows:

30 - Normal

31 - VENT

32 - B/L (Bi level)

34 - FOOT



Actuator operation check

By pressing the HOT button while in Mode Door Position check, you can actually send a signal to check the operation of the actuator manually. This is a bit complex, and will be expanded upon when a manual can viewed. Sensor recognition check Press the HOT switch again and a "5" will be indicated in the display section. If you press the "AMB" button (R32) or the windscreen defroster button (R33) in this status, the display will show the temperature sensed by each sensor. This will give you an indication also of which (if any) are faulty.

Temperatures will be displayed in the following order (R32):

5 -> Outside air temp -> Inside air temp -> Suction temp -> Refrigerant temp

R33 seems to have a different selection, with three temperatures being displayed.

Obviously if any of these temps seem excessively different from actual temperatures you have a problem!


If you depress the fan switch during the Sensor Recognition check, you will go to Calibration in which you can set the difference between the indicated temperature and sensed temperature.

While in Calibration press the HOT or COLD buttons to change the display by plus or minus 3 degrees in .5 degree increments (R32) or 1 degree increments (R33).

Hope that helps