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

BHE070301038W04

## Full-auto Air Conditioner

2 | Amount of air blown from vents does not change.
DESCRIPTION | • Malfunction in blower system.
POSSIBLE CAUSE | • Blower motor malfunction (Steps 3, 4, 12) • Blower unit malfunction (Steps 5-9) • Power transistor system malfunction (Steps 10, 11, 13, 14) • Climate control unit malfunction (Step 15)

• 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.

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | INSPECT A/C 7.5 A FUSE • Inspect A/C 7.5 A fuse. • Is it normal? | Yes | Go to next step.
No | Replace fuse, then go to Step 15. If fuse burns out immediately, go to next step.
2 | CHECK TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT OR ELSEWHERE • Turn ignition switch to ON position. • Recirculate air inside vehicle. • Does fan in blower unit rotate smoothly? | Yes | Go to Step 4.
No | Go to next step.
3 | INSPECT BLOWER UNIT INTAKE VENT • Is intake vent of blower unit clogged? | Yes | Remove obstruction, then go to Step 15.
No | Inspect if there are any obstruction in passage between blower unit to A/C unit, then go to Step 15.
4* | CHECK TO SEE WHETHER MALFUNCTION IS IN BLOWER RELAY SYSTEM OR POWER TRANSISTOR SYSTEM • Turn ignition switch to ON position. • Test voltage at the following terminal of blower motor. – Terminal B (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Go to Step 8.
No | Go to next step.
5* | CHECK 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 approx. 12 V? | Yes | Go to next step.
No | Repair wiring harness between blower relay and HEATER 40 A fuse, then go to Step 15.
6* | CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND GROND) OR ELSEWHERE • Test voltage at the following terminal of blower relay. – Terminal E (GND signal) • Is voltage approx. 0 V? | Yes | Go to next step.
No | Repair wiring harness between blower relay and ground, then go to Step 15.
7* | CHECK 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 approx. 12 V? | Yes | Repair wiring harness between blower relay and blower motor, then go to Step 15.
No | Replace blower relay, then go to Step 15.
8* | CHECK 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 approx. 12 V? | Yes | Go to next step.
No | Inspect blower motor, then go to Step 15. (See BLOWER MOTOR INSPECTION.)
9* | CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER MOTOR AND POWER TRANSISTOR) OR ELSEWHERE • Test voltage at the following terminal of power transistor. – Terminal B (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Go to next step.
No | Repair wiring harness between blower motor and power transistor, then go to Step 15.
10* | CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN POWER TRANSISTOR AND GROUND) OR ELSEWHERE • Test voltage at the following terminal of power transistor. – Terminal A (blower motor operation signal) • Is voltage approx. 0 V? | Yes | Go to next step.
No | Repair wiring harness between power transistor 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 voltage approx. 0 V? | Yes | Go to next step.
No | Remove obstruction, repair or replace fan and blower unit case, then go to Step 15.
12* | CHECK TO SEE WHETHER MALFUNCTION IS IN POWER TRANSISTOR OR ELSEWHERE • Disconnect power transistor connector. • Test voltage at the following terminal of power transistor. – Terminal B (blower motor control signal) • Is voltage approx. 10 V? | Yes | Replace power transistor, then go to Step 15.
No | Go to next step.
13* | CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN POWER TRANSISTOR AND A/C AMPLIFIER) OR ELSEWHERE • Turn ignition switch to LOCK position. • Disconnect A/C amplifier connector. • Inspect for continuity at the following terminals between power transistor and A/C amplifier. – Terminal D-1A (24-pin, blower motor control signal) – Terminal C-1B (24-pin, blower motor feedback signal) • Is there continuity? | Yes | Go to next step.
No | Repair wiring harness between power transistor and A/C amplifier, then go to Step 15.
14* | CHECK TO SEE WHETHER MALFUNCTION IS IN A/C AMPLIFIER OR WIRING HARNESS (SHORT TO GROUND BETWEEN POWER TRANSISTOR AND A/C AMPLIFIER) OR ELSEWHERE • Inspect for continuity at the following terminal between power transistor and ground. – Terminal A (24-pin, blower motor control signal)-ground • Is there continuity? | Yes | Repair wiring harness between power transistor and ground, then go to next step.
No | Replace A/C amplifier, then go to next step.
15 | VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR • Is air discharged from vent? | Yes | Troubleshooting completed. Explain repairs to customer.
No | Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.