Mazda 6 2002 Workshop Manual page 1156

STEP
4* INSPECT TO SEE WHETHER MALFUNCTION
IS IN BLOWER RELAY SYSTEM OR POWER
MOS FET SYSTEM
• Turn ignition switch to ON position.
• Test voltage at the following terminal of
blower motor.
— Terminal B (blower motor operation
signal)
• Is voltage approimately 12 V?
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 terminal of
blower relay.
— Terminal A (IG2 signal)
— Terminal C (B+ signal)
• Is voltage approimately 12 V?
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 approimately 0 V?
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 approimately 12 V?
8* INSPECT TO SEE WHETHER MALFUNCTION
IS IN BLOWER MOTOR OR ELSEWHERE
• Test voltage at the following terminal of
blower motor.
— Terminal B (blower motor operation
signal)
• Is voltage approimately 12 V?
9* INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN BLOWER MOTOR
AND POWER MOS FET) OR ELSEWHERE
• Test voltage at the following terminal of
power MOS FET.
— Terminal C (blower motor operation
signal)
• Is voltage approimately 12 V?
10* INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN POWER MOS FET
AND GROUND) OR ELSEWHERE
• Test voltage at the following terminal of
power MOS FET.
— Terminal A (blower motor operation
signal)
• Is voltage approimately 0 V?
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?
U–66
TROUBLESHOOTING
INSPECTION
Yes Go to Step 8.
No Go to net step.
Yes Go to net step.
No Repair wiring harness between blower relay and BLOWER
40 A fuse, then go to Step 15.
Yes Go to net step.
No Repair wiring harness between blower relay and ground,
then go to Step 15.
Yes Repair wiring harness between blower relay and blower
motor, then go to Step 15.
No Replace blower relay, then go to Step 15.
Yes Go to net step.
No Inspect blower motor, then go to Step 15.
Yes Go to net step.
No Repair wiring harness between blower motor and power
MOS FET, then go to Step 15.
Yes Go to net step.
No Repair wiring harness between power MOS FET and
ground, then go to Step 15.
Yes Go to net step.
No Remove obstruction, repair or replace fan and blower unit
case, then go to Step 15.
ACTION