Mazda CX-9 Grand Touring 2009 Manual page 1760

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, inspect to make sure connectors, terminals and wiring harness are
connected correctly and undamaged.
DIAGNOSTIC PROCEDURE
NO.7 AMOUNT OF AIR FROM REAR VENTS DOES NOT CHANGE DIAGNOSTIC PROCEDURE
STEP
INSPECT TO SEE WHETHER MALFUNCTION
IS IN REAR A/C UNIT OR ELSEWHERE
1
Turn the ignition switch to the ON position.
Turn the rear fan switch the ON position.
Does the blower motor rotate smoothly?
INSPECT REAR A/C UNIT INTAKE VENT
2
Is the rear A/C unit intake vent clogged?
INSPECT TO SEE WHETHER MALFUNCTION
IS IN REAR BLOWER RELAY SYSTEM OR
REAR POWER MOS FET
Turn the ignition switch to ON position.
Turn the rear fan switch to OFF position.
3*
Measure the voltage at the following rear blower
motor terminal.
Terminal B (rear blower motor operation
signal)
Is the voltage normal (B+)?
INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (OPEN OR SHORT
CIRCUIT BETWEEN FUSE BLOCK AND REAR
BLOWER RELAY) OR ELSEWHERE
4*
Measure the voltage at the following rear relay
terminals.
Terminal A (IG2 signal)
Terminal D (B+ signal)
Is the voltage approx. 12 V?
2008 Mazda CX-9 Grand Touring
2008 HVAC Symptom Troubleshooting (HVAC) - Mazda CX-9
Rear climate control unit malfunction
INSPECTION ACTION
Yes Go to the next step.
No Go to Step 3.
Remove obstruction, then go to Step
Yes
13.
Inspect if there are any obstructions
No in the rear A/C unit passage, then go
to Step 13.
Yes Go to the Step 7.
No Go to the next step.
Yes Go to the next step.
If the terminal A voltage is not
normal, repair or replace wiring
harness between A/C 7.5 A fuse and
rear blower relay.
No If the terminal D voltage is not
normal, repair or replace wiring
harness between R.HEATER 40 A
fuse and rear blower relay. Then go
to Step 13.