NO.6 WINDSHIELD FOGGED


BHE070301038W08

6

Windshield fogged.

DESCRIPTION

• A/C compressor does not operate while airflow mode is in DEFROSTER or HEAT/DEF modes.
• Air intake mode does not change to FRESH while airflow mode is in DEFROSTER or HEAT/DEF modes.

POSSIBLE CAUSE

• A/C amplifier (B+ signal) system malfunction (Steps 2, 4, 5)
• Air intake actuator malfunction (Steps 3, 7)
• A/C amplifier (RECIRCULATE, FRESH signal) system malfunction (Steps 9-11)
• Malfunction in blower unit air intake doors (Steps 12, 13)

• 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, check to make sure connectors, terminals and wiring harness are connected correctly and undamaged.

Diagnostic procedure

STEP

INSPECTION

ACTION

1

COOL AIR BLOW OUT INSPECTION

• When both A/C and fan switch in A/C amplifier are on, does cool air blow out from front vent?
Yes
Go to next step.
No
Go to Step 1 of troubleshooting index No.7.
2

INSPECT A/C AMPLIFIER POWER SUPPLY FUSE FOR B+ SIGNAL

• Is A/C amplifier power supply fuse for B+ signal normal?
Yes
Go to next step.
No
Inspect for a short to ground on blown fuse circuit.
• Repair or replace as necessary. Install appropriate amperage fuse.
3

INSPECT AIR INTAKE ACTUATOR

• Inspect air intake actuator.
– Is there grease on link?
– Is link securely and properly positioned?
– Is link free of obstructions?
• Are above items normal?
Yes
Go to next step.
No
Apply grease or install link properly and securely, remove obstruction, then go to Step 14.
4*

INSPECT WIRING HARNESS BETWEEN FUSE BLOCK AND A/C AMPLIFIER FOR CONTINUITY

• Disconnect A/C amplifier connector (16-pin).
• Turn ignition switch to ON position.
• Test voltage at A/C amplifier connector terminal 2A (B+ signal).
• Is voltage approx. 12 V?
Yes
Go to next step.
No
Repair wiring harness between fuse block and A/C amplifier, then go to Step 14.
5*

INSPECT WIRING HARNESS BETWEEN A/C AMPLIFIER AND GROUND FOR VOLTAGE

• Test voltage at A/C amplifier connector terminal 2N (Ground).
• Is voltage approx. 0V?
Yes
Go to next step.
No
Repair wiring harness between A/C amplifier and ground, then go to Step 14.
6

VERIFY WHETHER MALFUNCTION IS IN BLOWER UNIT AIR INTAKE DOOR OR ELSEWHERE

• Turn ignition switch to LOCK position.
• Connect A/C amplifier connector (16-pin).
• Remove air intake actuator.
• Turn ignition switch to ON position.
• Set fan switch to 4th position.
• Does air intake mode (RECIRCULATE, FRESH) change smoothly when air intake link is operated by hand?
Yes
Go to next step.
No
Go to Step 12.
7

INSPECT AIR INTAKE ACTUATOR

• Inspect air intake actuator.
• Is it normal?
Yes
Go to next step.
No
Replace air intake actuator, go to Step 14. (See AIR INTAKE ACTUATOR REMOVAL/INSTALLATION.)
8

INSPECT AIR INTAKE SELECTOR SWITCH AND DEFROSTER SWITCH IN A/C AMPLIFIER

• Test voltage at A/C amplifier connector (24-pin) terminals 1I and 1J.
• Is it normal?
Yes
Go to next step.
No
Replace A/C amplifier, then go to Step 14.
9*

INSPECT WIRING HARNESS BETWEEN A/C AMPLIFIER AND AIR INTAKE ACTUATOR FOR CONTINUITY

• Turn ignition switch to LOCK position.
• Is there continuity between the following A/C amplifier connector (24-pin) terminals and air intake actuator connector terminals?
– Terminal 1I-Terminal A (FRESH signal)
– Terminal 1J-Terminal C (RECIRCULATE signal)
Yes
Go to next step.
No
Repair wiring harness between A/C amplifier and air intake actuator, then go to Step 14.
10*

INSPECT WIRING HARNESS BETWEEN A/C AMPLIFIER AND AIR INTAKE ACTUATOR FOR SHORT TO GROUND

• Is there continuity between the following A/C amplifier connector (24-pin) terminals and ground?
– Terminal 1I (FRESH signal)
– Terminal 1J (RECIRCULATE signal)
Yes
Repair wiring harness between A/C amplifier and air intake actuator, then go to Step 14.
No
Go to next step.
11*

INSPECT WIRING HARNESS BETWEEN A/C AMPLIFIER AND AIR INTAKE ACTUATOR FOR SHORT TO B+

• Turn ignition switch to ON position
• Test voltage at the following A/C amplifier connector (24-pin) terminal:
– Terminal 1I (FRESH signal)
– Terminal 1J (RECIRCULATE signal)
• Is voltage approx. 12 V?
Yes
Repair wiring harness between A/C amplifier and air intake actuator, then go to Step 14.
No
Replace A/C amplifier, then go to Step 14.
12

INSPECT BLOWER UNIT AIR INTAKE DOOR

• Is there any foreign material or obstruction in blower unit air intake door?
Yes
Remove obstruction, then go to Step 14.
No
Go to next step.
13

VERIFY THAT BLOWER UNIT AIR INTAKE DOOR IS POSITIONED SECURELY AND PROPERLY

• Is blower unit air intake door securely and properly positioned?
Yes
Inspect air intake door for cracks or damage, then go to next step.
No
Install air intake door securely in proper position, then go to next step.
14

VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR

• Does malfunction disappear?
Yes
Troubleshooting completed.
Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.