Air Temperature Control (ATC) Request: Input/Output
The operation of the ATC request is via a switch being connected to earth. Voltage is supplied via pin 38 of connector C0637 of the ECM, at the point at when the switch is pressed the connection is made and the ATC clutch is engaged.
The ATC request can fail as follows:
- Open circuit.
- Short circuit to voltage supply.
- Short circuit to vehicle earth.
- Wiring loom fault.
In the event of an ATC request failure, the ATC system does not work.
Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by TestBook/T4. See Fig 1.