Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while doing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If there is a problem, check to make sure connectors, terminals and wiring harness are connected correctly and undamaged.
When checking intake motor drive signal, test it within 20 seconds after switching REC/FRESH mode. For that signal turns off after 20 seconds.

NO. 6 WINDSHIELD FOGGED DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	COOL AIR BLOW OUT INSPECTION When both A/C and fan switch in climate control unit are on, does cool air blow out from front vent?	Yes	Go to next step.
1		No	Go to Step 1 of troubleshooting index No. 8.
2	INSPECT CLIMATE CONTROL UNIT POWER SUPPLY FUSE FOR B+ SIGNAL Is climate control unit power supply fuse for B+ signal okay?	Yes	Go to next step.
2		No	Inspect for a short to ground on blown fuse circuit. Repair or replace as necessary. Install appropriate amperage fuse.
3	INSPECT AIR INTAKE ACTUATOR Inspect air intake actuator. Is there grease on link? Is link securely and properly positioned? Is link free of obstructions? Are above items okay?	Yes	Go to next step.
3		No	Apply grease or install link properly and securely, remove obstruction, then go to Step 14.
*4	INSPECT WIRING HARNESS BETWEEN FUSE BLOCK AND CLIMATE CONTROL UNIT FOR CONTINUITY Disconnect climate control unit connector (12-pin). Turn ignition switch to ON position. Test voltage at climate control unit terminal 2F (B+ signal). Is voltage approximately 12 V?	Yes	Go to next step.
*4		No	Repair wiring harness between fuse block and climate control unit, then go to Step 14.
*5	INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND GROUND FOR VOLTAGE Test voltage at climate control unit terminal 2L (Ground). Is voltage approximately 0V?	Yes	Go to next step.
*5		No	Repair wiring harness between climate control unit and ground, then go to Step 14.
6	VERIFY WHETHER MALFUNCTION IS IN BLOWER UNIT AIR INTAKE DOOR OR ELSEWHERE Turn ignition switch to LOCK position. Connect climate control unit connector (12-pin). Remove air intake actuator. Turn ignition switch to ON position. Set fan switch to 4th position. Does air intake mode (RECIRCULATE, FRESH) change smoothly when air intake link is operated by hand?	Yes	Go to next step.
6		No	Go to Step 12.
7	INSPECT AIR INTAKE ACTUATOR Inspect air intake actuator. (See AIR INTAKE ACTUATOR INSPECTION .) Is it okay?	Yes	Go to next step.
7		No	Replace air intake actuator, then go to Step 14.
8	INSPECT AIR INTAKE SELECTOR SWITCH AND DEFROSTER SWITCH IN CLIMATE CONTROL UNIT Test voltage at climate control unit terminals 2K and 2I. Is it okay?	Yes	Go to next step.
8		No	Replace climate control unit, then go to Step 14.
*9	INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND AIR INTAKE ACTUATOR FOR CONTINUITY Turn ignition switch to LOCK position. Is there continuity between the following climate control unit terminals and air intake actuator terminals? Terminal 2K-Terminal H (FRESH signal) Terminal 2I-Terminal G (RECIRCULATE signal)	Yes	Go to next step.
*9		No	Repair wiring harness between climate control unit and air intake actuator, then go to Step 14.
*10	INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND AIR INTAKE ACTUATOR FOR SHORT TO GROUND Is there continuity between the following climate control unit terminals and ground? Terminal 2K (FRESH signal) Terminal 2I (RECIRCULATE signal)	Yes	Repair wiring harness between climate control unit and air intake actuator, then go to Step 14.
*10		No	Go to next step.
*11	INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND AIR INTAKE ACTUATOR FOR SHORT TO B+ Turn ignition switch to ON position Test voltage at the following climate control unit terminals: Terminal 2K (FRESH signal) Terminal 2I (RECIRCULATE signal) Is voltage approximately 12 V?	Yes	Repair wiring harness between climate control unit and air intake actuator, then go to Step 14.
*11		No	Replace climate control unit, then go to Step 14.
12	INSPECT BLOWER UNIT AIR INTAKE DOOR Is there any foreign material or obstruction in blower unit air intake door?	Yes	Remove obstruction, then go to Step 14.
12		No	Go to next step.
13	VERIFY THAT BLOWER UNIT AIR INTAKE DOOR IS POSITIONED SECURELY AND PROPERLY Is blower unit air intake door securely and properly positioned?	Yes	Inspect air intake door for cracks or damage, then go to next step.
13		No	Install air intake door securely in proper position, then go to next step.
14	VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR Does malfunction disappear?	Yes	Troubleshooting completed. Explain repairs to customer.
14		No	Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.