Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

ALL SWITCH/DIAL OPERATION DOES NOT RESPOND (AUTO A/C) (US) DIAGNOSTIC PROCEDURE

Step	Inspection		Action
1*	INSPECT CLIMATE CONTROL UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT Inspect the power supply circuit for an open circuit and short to ground. (See CIRCUIT INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
1*		No	Repair or replace the malfunctioning location and perform the repair completion verification.
2*	INSPECT CLIMATE CONTROL UNIT GROUND CIRCUIT FOR OPEN CIRCUIT Inspect the ground circuit for an open circuit. (See CIRCUIT INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
2*		No	Repair or replace the malfunctioning location and perform the repair completion verification.
3*	INSPECT DASH-ELECTRICAL SUPPLY UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT Inspect the power supply circuit for an open circuit and short to ground. (See CIRCUIT INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
3*		No	Repair or replace the malfunctioning location and perform the repair completion verification.
4*	INSPECT DASH-ELECTRICAL SUPPLY UNIT GROUND CIRCUIT FOR OPEN CIRCUIT Inspect the ground circuit for an open circuit. (See CIRCUIT INSPECTION .) Is the circuit normal?	Yes	Replace the climate control unit, then go to the next step. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION (AUTO A/C) (US) .)
4*		No	Repair or replace the malfunctioning location and perform the repair completion verification.
Repair completion verification	VERIFY THAT MALFUNCTION SYMPTOM DOES NOT RECUR AFTER REPAIR Do the related parts operate according to the switch/dial operation of the climate control unit?	Yes	Troubleshooting completed. Explain repairs to customer.
Repair completion verification		No	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(US)] .) If the CAN communication is normal, perform the diagnosis from Step 1.