No. 24 A/C Is Always On Or A/C Compressor Runs Continuously: Notes

WARNING: This page is about a different car, the 2014 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

NO. 24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY (SKYACTIV-G 2.5) DESCRIPTION AND POSSIBLE CAUSE

24	A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE	PCM, instrument cluster or climate control unit DTC is stored Short to power supply in wiring harness between A/C relay terminal D and magnetic clutch terminal A Magnetic clutch engagement is stuck Climate control unit malfunction (Climate control unit always transmits A/C request signal) A/C relay is stuck closed Short to ground in wiring harness between A/C relay terminal E and PCM terminal 2AF
Courtesy of MAZDA MOTORS CORP.

CAUTION:

Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.