Test K: The Air Conditioning (A/C) Is Always On

PINPOINT TEST K: THE AIR CONDITIONING (A/C) IS ALWAYS ON

Normal Operation
Under normal operation, when A/C is requested in electronic automatic temperature control (EATC) or dual automatic temperature control (DATC) systems, a message is sent over the medium-speed controller area network (MS-CAN) bus to the instrument cluster, then from the instrument cluster through the high-speed controller area network (HS-CAN) bus to the PCM; or a voltage is sent to the instrument cluster through circuit CH434 (GY/YE), then a message is sent from the instrument cluster through the HS-CAN bus to the PCM electronic manual temperature control (EMTC) systems.

Ignition voltage for the A/C clutch relay switch is provided through circuit SBB25 (RD). When the PCM energizes the relay, ignition voltage is supplied to the A/C clutch through circuit CH401 (VT/WH). Ground is supplied for the A/C clutch through circuit GD121 (BK/YE).

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM
- HVAC module - EATC
- HVAC module - DATC
- HVAC module - EMTC
- A/C evaporator discharge temperature sensor
- A/C pressure transducer
- A/C control relay
- A/C clutch air gap

K1-K5:

K5-K8:

K8-K11: