Mazda CX-9 Grand Touring 2009 Manual page 1747

INSPECT FRONT A/C UNIT INTAKE VENT
3
Is front A/C unit intake vent clogged?
INSPECT TO SEE WHETHER MALFUNCTION IS IN
FRONT BLOWER RELAY SYSTEM OR FRONT
POWER MOS FET SYSTEM
Turn the ignition switch to ON position.
4*
Turn the fan switch to OFF position.
Measure the voltage at the following front blower motor
terminal.
Terminal B (blower motor operation signal)
Is voltage approx. 12 V?
INSPECT TO SEE WHETHER MALFUNCTION IS IN
WIRING HARNESS (OPEN CIRCUIT BETWEEN FUSE
BLOCK AND FRONT BLOWER RELAY) OR
ELSEWHERE
5*
Measure the voltage at the following front blower relay
terminals.
Terminal B (IG2 signal)
Terminal E (B+ signal)
Is the voltage approx. 12 V?
INSPECT TO SEE WHETHER MALFUNCTION IS IN
WIRING HARNESS (OPEN CIRCUIT BETWEEN
FRONT BLOWER RELAY AND GROUND) OR
ELSEWHERE
6*
Measure the voltage at the following front blower relay
terminal.
Terminal D (GND signal)
Is the voltage approx. 0 V?
INSPECT TO SEE WHETHER MALFUNCTION IS IN
WIRING HARNESS (OPEN OR SHORT CIRCUIT
BETWEEN FRONT BLOWER RELAY AND FRONT
BLOWER MOTOR) OR BLOWER RELAY
7*
Measure the voltage at the following front blower relay
terminal.
Terminal A (blower motor operation signal)
Is the voltage approx. 12 V?
INSPECT TO SEE WHETHER MALFUNCTION IS IN
2008 Mazda CX-9 Grand Touring
2008 HVAC Symptom Troubleshooting (HVAC) - Mazda CX-9
Step 15.
Inspect if there are any
No obstruction in the A/C unit
passage, then go to Step 15.
Yes Go to Step 8.
No Go to the next step.
Yes Go to the next step.
Repair the wiring harness
between the front blower relay
No
and A/C 7.5A HEATER 50 A
fuse, then go to Step 15.
Yes Go to the next step.
Repair the wiring harness
No between the front blower relay
and ground, then go to Step 15.
Repair the wiring harness
between the front blower relay
Yes
and blower motor, then go to
Step 15.
Replace the front blower relay,
No
then go to Step 15.