Mazda RX-8 Workshop Manual page 781

3 Disconnect the refrigerant pressure switch connector.
Start the engine and turn the A/C switch on.
NOTE:
The A/C should not work when
disconnecting the connector. If the A/C
remains working, a short to GND circuit
may be present.
Does the A/C remain working?
4 Reconnect the refrigerant pressure switch connector.
Disconnect the A/C amplifier connector.
NOTE:
The A/C should not work when
disconnecting the connector. If the A/C
remains working, a short to GND circuit
may be present.
Does the A/C remain working?
5 Verify test results.
If normal, return to the diagnostic index to service any additional symptoms.
If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.
If both items normal, go to the
next step.
No Inspect if the circuit between A/C
relay and magnetic clutch shorts
to the battery power circuit.
If the circuit is normal, inspect
the magnetic clutch for stuck
engagement or clearance.
Yes Inspect for short to GND circuit
between refrigerant pressure
switch and PCM terminal 1AU.
No Go to the next step.
Yes Inspect for short to GND circuit
between A/C amplifier and
refrigerant pressure switch.
No Inspect for open or short circuit
between climate control unit and
A/C amplifier.
If the wiring harnesses are
normal, replace the climate
control unit (A/C switch is stuck
ON).
(See CLIMATE CONTROL UNIT
REMOVAL/INSTALLATION
[MANUAL AIR
(See CLIMATE CONTROL UNIT
REMOVAL/INSTALLATION [FULL-
AUTO AIR CONDITIONER].)
CONDITIONER].)