Troubleshooting - Mazda 2002 6 Workshop Manual

STEP
12* INSPECT TO SEE WHETHER MALFUNCTION
IS IN POWER MOS FET OR ELSEWHERE
• Disconnect power MOS FET connector.
• Test voltage at the following terminal of
power MOS FET.
— Terminal B (blower motor control signal)
• Is voltage approximately 10 V?
13* INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN POWER MOS FET
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 power MOS FET and
climate control unit.
— Terminal B—1C (24-pin, blower motor
control signal)
— Terminal C—1A (24-pin, blower motor
feedback signal)
• Is there continuity?
14* INSPECT TO SEE WHETHER MALFUNCTION
IS IN CLIMATE CONTROL UNIT OR WIRING
HARNESS (SHORT TO GROUND BETWEEN
POWER MOS FET AND CLIMATE CONTROL
UNIT)
• Inspect for continuity at the following terminal
between power MOS FET and ground.
— Terminal B (blower motor control signal)—
ground
• Is there continuity?
15 CONFIRM THAT MALFUNCTION SYMPTOMS
DO NOT RECUR AFTER REPAIR
• Is air discharged from vent?
End Of Sie
NO.3 AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE
Manual Air Conditioner
3 Amount of air blown from vents does not change.
• Malfunction in blower system.
DESCRIPTION
• Blower relay, blower motor, resistor, fan switch malfunction (Step 1)
POSSIBLE
• Blower unit malfunction (Steps 2—4)
CAUSE
Diagnostic procedure
STEP
1 INSPECT BLOWER SYSTEM
• Inspect the following systems and electrical
parts.
— Blower relay
— Blower motor
— Resistor
— Fan switch
— Related wiring harnesses
• Are they okay?
2 CHECK TO SEE WHETHER MALFUNCTION
IS IN BLOWER UNIT OR ELSEWHERE
• Turn ignition switch to ON position.
• Turn fan switch on.
• Recirculate air inside vehicle.
• Does fan in blower unit rotate smoothly?

TROUBLESHOOTING

INSPECTION
INSPECTION
Yes Replace power MOS FET, then go to Step 15.
No Go to next step.
Yes Go to next step.
No Repair wiring harness between power MOS FET and
climate control unit, then go to Step 15.
Yes Repair wiring harness between power MOS FET and
ground, then go to next step.
No Replace climate control unit, then go to next step.
Yes Troubleshooting completed.
Explain repairs to customer.
No Recheck malfunction symptoms, then repeat from Step 1 if
malfunction recurs.
Yes Go to next step.
No Repair or replace malfunctioning part, then go to Step 5.
Yes Go to Step 4.
No Go to next step.
ACTION
A6E858001038W05
ACTION
U–67
U