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 performing 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 harnesses are connected correctly and undamaged.

NO. 2 AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	INSPECT BLOWER 40 A FUSE Inspect BLOWER 40 A fuse. Is it okay?	Yes	Go to next step.
1		No	Replace fuse, then go to Step 15. If fuse burns out immediately, go to next step.
2	INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT OR ELSEWHERE Turn ignition switch to ON position. Turn the fan switch to ON position. Recirculate air inside vehicle. Does blower unit fan rotate smoothly?	Yes	Go to next step.
2		No	Go to Step 4.
3	INSPECT BLOWER UNIT INTAKE VENT Is intake vent of blower unit clogged?	Yes	Remove obstruction, then go to Step 15.
3		No	Inspect if there are any obstructions in passage between blower unit to A/C unit, then go to Step 15.
4*	INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER RELAY SYSTEM OR PWM UNIT SYSTEM Turn ignition switch to ON position. Turn the fan switch to OFF position. Test voltage at the following terminal of blower motor: Terminal B (blower motor operation signal) Is voltage approximately 12 V?	Yes	Go to Step 8.
4*		No	Go to next step.
5*	INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN FUSE BLOCK AND BLOWER RELAY) OR ELSEWHERE Test voltage at the following terminals of blower relay: Terminal A (IG2 signal) Terminal C (B+ signal) Is voltage approximately 12 V?	Yes	Go to next step.
5*		No	Repair wiring harness between blower relay and BLOWER 40 A fuse, then go to Step 15.
6*	INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND GROUND) OR ELSEWHERE Test voltage at the following terminal of blower relay: Terminal E (GND signal) Is voltage approximately 0 V?	Yes	Go to next step.
6*		No	Repair wiring harness between blower relay and ground, then go to Step 15.
7*	INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND BLOWER MOTOR) OR BLOWER RELAY Test voltage at the following terminal of blower relay: Terminal D (blower motor operation signal) Is voltage approximately 12 V?	Yes	Repair wiring harness between blower relay and blower motor, then go to Step 15.
7*		No	Replace blower relay, then go to Step 15.
8*	INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER MOTOR OR ELSEWHERE Test voltage at the following terminal of blower motor: Terminal A (blower motor operation signal) Is voltage approximately 12 V?	Yes	Go to next step.
8*		No	Inspect blower motor, then go to Step 15.
9*	INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER MOTOR AND PWM UNIT) OR ELSEWHERE Test voltage at the following terminal of PWM unit: Terminal 2C and 1A (blower motor operation signal) Is voltage approximately 12 V?	Yes	Go to next step.
9*		No	Repair wiring harness between blower motor and PWM unit, then go to Step 15.
10*	INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN PWM UNIT AND GROUND) OR ELSEWHERE Test voltage at the following terminal of PWM unit: Terminal 1B (blower motor operation signal) Is voltage approximately 0 V?	Yes	Go to next step.
10*		No	Repair wiring harness between PWM unit and ground, then go to Step 15.
11	INSPECT BLOWER UNIT Inspect fan in blower unit. Is fan free of interference with blower unit case? Is fan free of foreign material and obstruction? Is fan okay?	Yes	Go to next step.
11		No	Remove obstruction, repair or replace fan and blower unit case, then go to Step 15.
12*	INSPECT TO SEE WHETHER MALFUNCTION IS IN PWM UNIT OR ELSEWHERE Turn the fan switch to 1st position from off. Test voltage at the following terminal of PWM unit: Terminal 2A (blower motor control signal) Does voltage change from 12 V to 9 V?	Yes	Replace PWM unit, then go to Step 15.
12*		No	Go to next step.
13*	INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN PWM UNIT AND CLIMATE CONTROL UNIT) OR ELSEWHERE Turn ignition switch to LOCK position. Disconnect climate control unit connector. Inspect for continuity at the following terminals between PWM unit and climate control unit: Terminal 2A-1C (blower motor control signal) Is there continuity?	Yes	Go to next step.
13*		No	Repair wiring harness between PWM unit and climate control unit, then go to Step 15.
14*	INSPECT TO SEE WHETHER MALFUNCTION IS IN CLIMATE CONTROL UNIT OR WIRING HARNESS (SHORT TO GROUND BETWEEN PWM UNIT AND CLIMATE CONTROL UNIT) Inspect for continuity between the following PWM unit terminal and ground. Terminal 2A (blower motor control signal) Is there continuity?	Yes	Repair wiring harness between PWM unit and ground, then go to next step.
14*		No	Replace climate control unit, then go to next step.
15	CONFIRM THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR Is air discharged from vent?	Yes	Troubleshooting completed. Explain repairs to customer.
15		No	Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.