| Number | X-pin, colour | Description |
|---|---|---|
| X126 | 4 -pin, Black | Plug connector High pressure switch |
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 E Q439 Plusversorgung Magnetkupplung B8 Druckschalter Hochdruck | E | Positive supply, magnetic clutch | Heating and A/C control module |
| 2 | M | Ground | Ground point |
| 3 | E | Activation terminal 85 | Auxiliary fan stage 2 relay |
| 4 | A | Signal, magnetic clutch A/C compressor | Solenoid clutch |