Operation CHARM: Car repair manuals for everyone.

Bus (+/-) Signals Open/No Response From HVAC

Tests 1 - 3:




Tests 4 - 5:




SYMPTOM
BUS +/- SIGNALS OPEN OR NO RESPONSE FROM HVAC

POSSIBLE CAUSES
- Attempt to communicate with the BCM
- Ground circuit open
- Ignition switch circuit open
- Open PCI bus circuit
- A/C heater control