Mazda MX-5 Miata Sport 2007 Manual page 2036

2007 ENGINE PERFORMANCE Symptom Troubleshooting - MX-5 Miata
NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
[LF]
POSSIBLE CAUSE & DESCRIPTION (A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS
CONTINUOUSLY)
DESCRIPTION
POSSIBLE CAUSE
DIAGNOSTIC PROCEDURE
A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY DIAGNOSTIC
PROCEDURE TABLE
STEP
1
2
2007 Mazda MX-5 Miata Sport
If vehicle is not repaired or additional diagnostic

information is not available, replace the PCM.
(See PCM REMOVAL/INSTALLATION [LF] .)
24
INSPECTION
Connect the M-MDS or
equivalent to the DLC-2.
Turn the ignition switch
to the ON position
(Engine off).
Retrieve any DTCs.
Are there any DTCs
displayed?
Start the engine and idle
it.
Turn the A/C switch on.
Remove the A/C relay.
Does the A/C magnetic
clutch disengage?
A/C IS ALWAYS ON OR A/C COMPRESSOR
RUNS CONTINUOUSLY.
A/C compressor magnetic clutch does not
disengage.
A/C compressor magnetic clutch engagement

is stuck.
A/C relay is stuck closed.

Short to GND in wiring harness between A/C

switch and PCM
Short to GND in wiring harness between A/C

relay and PCM
Short circuit to battery power in A/C relay to

magnetic clutch
RESULTS
Yes
No
Yes
ACTION
DTC is displayed:
Go to the appropriate
DTC inspection.
(See DTC TABLE
[LF] .)
No DTC is displayed:
Go to the next step.
Inspect for the following:
A/C relay is stuck

closed.
Short to GND in

wiring harness