| Number | X-pin, color | Description |
|---|---|---|
| X610 | 26-pin, blue | Connector 3 Heating and A/C control module |
| X611 | 18-pin, natural | Connector 4 Heating and A/C control module |
| X613 | 3-pin, natural | Connector 2 Heating and A/C control module |
| X614 | 3-pin, black | Connector Heating and A/C control module |
| X18153 | 3-pin, black | Connector 5 Heating and A/C control module |
| X18341 | 3-pin, black | Connector 0 Heating and A/C control module |
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | E | Voltage supply, terminal 15 | Fuse F20 |
| 2 | A | Signal, A/C compressor OFF (M51) A/C compressor signal | DDE control module Engine control module (DME) Digital diesel electronics control unit |
| 3 | A | Signal, A/C compressor ON (M51) | DDE control module |
| 4 | A | A/C system standby signal | DDE control module |
| 5 | A | Rear window defogger relay control | Rear defogger relay |
| 6 | A | Front defogger/washer jets relay control | Front defogger/washer jets relay |
| 7 | E | Pressure signal | High pressure switch |
| 8 | A | Blower control voltage | Final stage unit |
| 9 | Not used | ||
| 10 | M | Circulation (AUC) heater component ground | Automatic air recirculation sensor |
| 11 | M | Ground High pressure switch | High pressure switch |
| 12 | E | Consumer cut-off signal | General module |
| 13 | Not used | ||
| 14 | A | Auxiliary water pump control | Auxiliary water pump |
| 15 | A | Blower relay control | Blower relay |
| 16 | Not used | ||
| 17 | A | Auxiliary fan normal speed relay control | Auxiliary fan normal speed relay |
| 18 | E | Nighttime illumination signal | Terminal 58g splice |
| 19 | E/A | K-bus signal line | K-bus splice |
| 20 | A | Left water valve control | Water valve assembly, Left valve |
| 21 | A | Right water valve control | Water valve assembly, Right valve |
| 22 | A | Power High pressure switch | High pressure switch |
| 23 | A | Sensor voltage supply | Automatic air recirculation sensor |
| 24 | E | Negative activation | Automatic air recirculation sensor |
| 25 | A | Circulation (AUC) heating control | Automatic air recirculation sensor |
| 26 | Not used | ||
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | E | Actuating signal | Fresh air flap motor |
| 2 | A | Actuating signal | Fresh air flap motor |
| 3 | A | Actuating signal | Fresh air flap motor |
| 4 | E | Actuating signal | Fresh air flap motor |
| 5 | E | Mixing air actuator desired value | Rear mixing actuator |
| 6 | A | Sensors (+) | Mixing actuator, Rear mixing actuator |
| 7 | E | Mixing air actuator desired value | Mixing actuator |
| 8 | E | Sensor signal | Right ventilation sensor |
| 9 | E | Sensor signal | Left ventilation sensor |
| 10 | E | Ventilation ON signal | Rear ventilation switch |
| 11 | Not used | ||
| 12 | Not used | ||
| 13 | Not used | ||
| 14 | M | Component ground | Sensor and actuator |
| 15 | E | Sensor signal | Evaporator temperature sensor |
| 16 | E | Sensor signal | RH heat exchanger temperature sensor |
| 17 | E | Sensor signal | LH heat exchanger temperature sensor |
| 18 | Not used | ||
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | A | Control voltage | Left actuator motors and recirculated air |
| 2 | M | Actuator motors ground | Left actuator motors and recirculated air |
| 3 | E/A | MI-bus | Left actuator motors and recirculated air |
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | A | Control voltage | Right actuator motors and defrosting |
| 2 | M | Actuator motors ground | Right actuator motors and defrosting |
| 3 | E/A | MI-bus | Right actuator motors and defrosting |
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | A | Park heating ON signal | up to 1995_08 Independent park/auxiliary heating as of 1995_09 Receiver, independent heating |
| 2 | A | Control voltage | Solenoid valve 2 park heating/ventilation |
| 3 | E | Park heating ON feedback signal | Independent park/auxiliary heating |
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | A | Magnetic clutch voltage supply | High pressure switch (M51) Heating and A/C control module |
| 2 | E | Terminal 30 voltage supply | Fuse F11 |
| 3 | M | Ground | Ground X492 |