Preparation For Test

MANUAL AND OPTICAL FUNCTION TEST OF AUTOMATIC CLIMATE CONTROL (ACC):
- The manual test permits checking the operation of all components of Automatic Climate Control system (ACC).
- Additional tests for finding the cause of the fault are only required in the event of deviations from the functions or air outlets shown here.

Test Preparation:
1. Run engine at idle and at operating temperature during entire test.

Lever For Center Nozzle:

2. Open lever (arrow) for center nozzles, except USA models, as well as lever for side nozzles left and right.
3. Remove the glove box.

Test Notes:
1. During electric test on 2-pole coupler of monovalve (with voltmeter, test lamp) be sure to avoid a short which may destroy the electronic switching unit for temperature control.
2. At room temperatures > 25°C the cycling of the heating water valve cannot be readily shown during 2nd and 6th test. For this purpose, the vehicle interior should be cooled down to approx. 22°C (with doors and windows, as well as sliding top closed).

Adapter # 126 589 03 21 00:

3. Additional tests can be made with an adapter for automatic climate control.

Pushbutton Control Unit:

Image Reference;
3 Temperature dial
5 Blower switch
a-e Function selection buttons
f Max. blower stage (6th stage)
g Automatic blower (2nd-5th stage)
h Min. blower stage (1st stage)

Special Operating Conditions:
1. Only one button at a time should be pushed on principle. The operating conditions described below are therefore not included in test scope. They are mentioned only to assist customers if such a condition has been established by chance. No damage will occur, even if the vehicle is driven for an extended period.
a) All buttons "a" - "e" not pushed: Operating conditions similar to "c", but the lowest automatic blower stage will then be raised to 3rd stage.
b) Button "e" pushed in combination with another button: System always in switched-off condition.
c) Buttons "c" and "d" pushed at the same time: Operating condition similar to "d", but 3rd blower stage will drop to 2nd stage.
d) Buttons "b" and "c" pushed at the same time: Operating condition similar to "b", but 3rd blower stage will drop to 2nd stage.
e) Buttons "a" and "b" pushed at the same time: Operating condition similar to "a", but leg room flaps will be additionally opened.
f) Operation of button "a" (DEF) will always predominate in relation to selector dial and blower.
g) Buttons "b" and "d" pushed at the same time: Function similar to "b", but compressor will be switched off.

Significance Of Arrows In Graphic Displays Of Tests:
Arrows, large Arrows, small
Outside Air grey
Cooled Air black
Heated Air white
Air Outlet (warm) white