Mazda CX-9 Grand Touring 2009 Manual page 1375

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Start the engine and idle it.
Turn the A/C switch on.
2
Remove the A/C relay.
Does the A/C magnetic clutch disengage?
Disconnect refrigerant pressure switch
connector.
Start the engine and turn A/C switch on.
NOTE:
A/C should not work when
3
disconnecting connector. If A/C
remains working, short to GND circuit
may be present.
Does the A/C remain working?
Reconnect refrigerant pressure switch
connector.
Turn off A/C switch.
NOTE:
4
A/C should not work when turning A/C
switch off. If A/C remains working,
short to GND circuit may be present.
Does A/C remain working?
Verify test results.
If normal, return to diagnostic index to service any additional symptoms.
5
(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)
If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.
2008 Mazda CX-9 Grand Touring
Yes
No
Yes
No
Yes
No
A/C relay is stuck closed.
Short to GND in wiring harness
between A/C relay and PCM
terminal 1N.
If both items normal, go to the next
step.
Inspect if circuit between the A/C
relay and magnetic clutch shorts to
battery power circuit.
If the circuit is normal, inspect the
magnetic clutch for stuck engagement
or clearance.
Inspect for short to GND in wiring
harness between refrigerant pressure
switch and PCM terminal 1R.
Go to the next step.
Inspect following:
Short to GND in wiring harness
between A/C switch and A/C
amplifier
Short to GND circuit between
A/C amplifier and refrigerant
pressure switch
Inspect whether A/C switch is stuck
closed.