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Climate Control
Volume 1
Diagnostic Manual, Climate Control, Volume 1

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LOCATION:    3.1 Air Conditioning (A/C)    >   23 Electrical Test Program - Test


Electrical Test Program - Test

Test scope Test connection Test condition Nominal value Possible cause/Remedy
1.0
In-car temperature sensor with aspirator
blower (B10/4)
Resistance

19

11
N22




20

20
on left connector (1)

Ignition: OFF
Disconnect test cable from pushbutton control module 		oC k
10 18.3 - 21.5
15 15.2 - 17.5
20 11.5 - 13.5
25 9.5 - 10.5
30 7.5 - 8.5
35 6.0 - 7.0
40 4.5 - 5.5
45 3.5 - 4.5
Wires from pushbutton control module (N22) to sensor B10/4 via connector (X85/2),
B10/4.
2.0
Outside temperature sensor (B10/5)
Resistance

19

12
N22





20

20
on left connector (1)

Ignition: OFF
Disconnect test cable from pushbutton control module 		oC k
10 5.0 - 6.0
15 4.0 - 4.6
20 3.1 - 3.9
25 2.4 - 3.0
30 1.9 - 2.3
35 1.6 - 2.0
40 1.4 - 1.6
45 1.1 - 1.3
Wires from pushbutton control module (N22) to sensor B10/5,
B10/5.
3.0
Evaporator temperature sensor (B10/6) 1)
Resistance

19

8
N22




20

20
on left connector (1)

Ignition: OFF
Disconnect test cable from pushbutton control module 		oC k
0 8.1 - 9.9
5 6.3 - 7.7
10 5.0 - 6.0
15 4.0 - 4.6
20 3.1 - 3.9
25 2.4 - 3.0
30 1.9 - 2.3
35 1.6 - 2.0
40 1.4 - 1.6
45 1.1 - 1.3
Wires from pushbutton control module (N22) to sensor B10/6,
B10/6.
4.0
Heater core temperature sensor (B10/1)
Resistance

19

10
N22




20

20
on left connector (1)

Ignition: OFF
Disconnect test cable from pushbutton control module 		oC k
10 18.3 - 21.5
15 15.2 - 17.5
20 11.5 - 13.5
25 9.5 - 10.5
30 7.5 - 8.5
35 6.0 - 7.0
40 4.5 - 5.5
45 3.5 - 4.5
Wires from pushbutton control module (N22) to sensor B10/1,
B10/1.
5.0
ECT sensor (A/C)
Resistance

19

7
N22




20

20
on left connector (1)

Ignition: OFF
Disconnect test cable from pushbutton control module 		oC
20 5000 - 8000
60 900 - 1800
85 460 - 650
100 300 - 400
110 230 - 290
120 180 - 220
130 135 - 175
Wires from pushbutton control module (N22) to sensor B10/8,
B10/8.
6.0
Center and side air outlet flap control module, left air outlet adjuster (N18/2r1)
Voltage

20
N22


16
on left connector (1)
Move left air outlet adjuster completely to the right (outlet closed)

completely to the left (outlet open)
0.6 - 0.9 V

continuous, no steps

3.9 - 4.5 V 		Wires from control module (N22)
to left air outlet
adjuster (N18/2r1),
Center and side air outlet flap control module (N18/2).
7.0
Center and side air outlet flap control module, center air outlet adjuster (N18/2r2)
Voltage

20
N22


18
on left connector (1)
Move center air outlet adjuster completely to the right (outlet closed)

completely to the left (outlet open)
0.6 - 0.9 V

continuous, no steps

3.9 - 4.5 V 		Wires from N22 to center air outlet
adjuster (N18/2r2),
N18/2.
8.0
Center and side air outlet flap control module, right air outlet adjuster (N18/2r3)
Voltage

20
N22


14
on left connector (1)
Move right air outlet adjuster completely to the right (outlet closed)

completely to the left (outlet open)
0.6 - 0.9 V

continuous, no steps

3.9 - 4.5 V 		Wires from N22 to right air outlet
adjuster (N18/2r3),
N18/2.
9.0   Center and side air outlet flap control module, pushbutton
"cold" (N18/2s1)
Voltage


19
N22


4
on left connector (1)
Press blue switch on center air outlet and hold 		< 0.1 V Wires from N22 to cold pushbutton switch (N18/2s1),
Center and side air outlet flap control module (N18/2).
10.0   Center and side air outlet flap control module, pushbutton
"warm" (N18/2s2)
Voltage


19
N22


3
on left connector (1)
Press red switch on center air outlet and hold 		< 0.1 V Wires from N22 to cold pushbutton switch (N18/2s2),
N18/2.
11.0
Left air outlet feedback potentiometer (R23/1)
Voltage

20
N22


15
on left connector (1)
Move left air outlet adjuster completely to the right (outlet closed)

completely to the left (outlet open)
0.7 - 1.1 V

Continuous, no steps

3.5 - 4.8 V 		Wires from N22 to feedback potentiometer (R23/1),
R23/1, Incorrect adjustment or defective, replace vacuum element.
12.0
Center air outlet feedback potentiometer (R23/3)
Voltage

20
N22


17
on left connector (1)
Move center air outlet adjuster completely to the right (outlet closed)

completely to the left (outlet open)
0.7 - 1.1 V

Continuous, no steps

3.5 - 4.8 V 		Wires from N22 to feedback potentiometer (R23/3),
R23/3, incorrect adjustment or defective, replace vacuum element.
13.0
Right air outlet feedback potentiometer (R23/2)
Voltage

20
N22


13
on left connector (1)
Move right air outlet adjuster completely to the right (outlet closed)

completely to the left (outlet open)
0.7 - 1.1 V

Continuous, no steps

3.5 - 4.8 V 		Wires from N22 to feedback potentiometer (R23/2),
R23/2, incorrect adjustment or defective, replace vacuum element.
14.0   Left soft top fabric bow switch group (A22)
Voltage

19
N22


6
on left connector (1)
Soft top closed

Soft top open

< 0.1 V

> 10 V 		Wires from N22 to left soft top bow switch group (A22) via connectors (X85/2, X18/3).
1) If the A/C system was in use immediately before the test, the temperature at the evaporator temperature sensor will be lower than the outside air temperature.

Test Conditions

1. Ignition: OFF
2. Disconnect both connectors from A/C pushbutton control
module (N22).
3. Disconnect test cable from left connector and reconnect to right connector.

Test scope Test connection Test condition Nominal value Possible cause/Remedy
15.0

Monovalve (Y19)

18
N22



20
  11 - 19 Wires from N22 to Y19,
Y19.

Test Conditions

1. Connect test cable to right connector of A/C pushbutton control module (N22).
2. Connect wiring harness to left connector of A/C pushbutton control module.
3. Ignition: ON

Test scope Test connection Test condition Nominal value Possible cause/Remedy
16.0   A/C pushbutton control module (N22)
Voltage supply (circuit 30)




N22

1
on right connector (2) > 10 V Fuse 10 (F1-10), circuit 30,
Wires from N22 to fuse F1-10 open.
17.0   A/C pushbutton control module (N22)
Voltage supply (circuit 15)




N22

19
on right connector (2) > 10 V Fuse 7 (F1-7), circuit 15,
Wires from N22 to fuse F1-7 open.
18.0   A/C pushbutton control module (N22)
Voltage supply, output




N22

20
on right connector (2)
> 10 V N22.
19.0   Mono valve (Y19)
Ground connection

18
N22



20
on right connector Temperature selector (2)wheel set at "MIN". After 10 seconds
> 10 V
N22.
20.0
Auxiliary coolant pump (M13) and and additional function test by manual touch
Ground connection


16
N22



20
on right connector (2)
Temperature selector wheel set at "MAX" 		After approx. 50 seconds
> 10 V 		A/C pushbutton control
module (N22).
21.0 Switchover valve
block (Y11)
Data transfer

7
N22



20
on right connector (2) Voltage oscillates between
0 - 8 V
N22.
22.0   Electronic blower
regulator (N29)
Voltage supply



N22

11
on right connector (2)
Blower speeds: 1
2
3
4




0.8 - 1.2 V
1.8 - 2.2 V
2.7 - 3.3 V
> 5 V 		N22.
23.0
Auxiliary fan (M4)
Stage 1

12
N22



20
on right connector (2)
Press
Outside temperature
above 86 oF 		> 10 V
and auxiliary fan running in
stage 1
A/C pushbutton control
module (N22).
24.0
Auxiliary fan (M4)
Stage 2

13
N22



20
on right connector (2)
Disconnect and bridge ETC sensor plug (B10/8) 		> 10 V
and auxiliary fan running in
stage 2
N22.
25.0
A/C compressor (A9)
Ground connection 1)

14
N22



20
on right connector (2)
Press 		After 10 seconds
> 10 V
N22.
1) If the A/C compressor does not engage, check compressor shut-off 24 .



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