A/C system does not come on (both fans and the A/C compressor do not work); heater is OK
Diagnostic procedure
  1. A/C signal circuit troubleshooting A/C pressure sensor troubleshooting: A/C pressure sensor circuit low voltage, R20A3 engine model, K24Z3 engine model, A/C pressure sensor circuit high voltage, R20A3 engine model, K24Z3 engine model
Also check for
  • HVAC DTCs
  • Powertrain DTCs, R20A3 engine model, K24Z3 engine model
  • Cleanliness and tightness of all terminals