• 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
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INSPECTION
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ACTION
|
|
---|---|---|---|
1
|
INSPECT COOLANT TEMPERATURE
• Is coolant sufficiently warmed up?
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Yes
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Go to next step.
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No
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Warm engine up, then go to Step 19.
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2
|
CHECK CIRCUITS COMMON TO BOTH AIR MIX ACTUATOR AND AIRFLOW MODE ACTUATOR
• Does airflow mode change when operating airflow mode selector switch?
|
Yes
|
Go to Step 10.
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No
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Go to next step.
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3
|
CHECK TO SEE WHETHER PROBLEM IS IN AIR MIX ACTUATOR +5 V SIGNAL OR POTENTIOMETER GND SIGNAL
• Is air mix actuator set at MAX HOT and airflow mode actuator at VENT?
(Verify position of air mix actuator link and airflow mode actuator link.)
|
Yes
|
Go to next step.
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No
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Go to Step 8. (Set actuator at MAX COLD and DEFROSTER.)
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4*
|
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR) OR ELSEWHERE
• Turn the ignition switch to ON position.
• Is there voltage of approx. 5 V at A/C amplifier connector (16-pin) terminal 2P (+5 V signal)?
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Yes
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Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
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No
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Go to next step.
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||
5*
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CHECK TO SEE WHETHER MALFUNCTION IS IN AIR MIX ACTUATOR (SHORT TO GROUND) OR ELSEWHERE
• Disconnect air mix actuator connector.
• Is there voltage of approx. 5 V at A/C amplifier connector (16-pin) terminal 2P (+5 V signal)?
|
Yes
|
Inspect air mix actuator, then go to Step 19. (See AIR MIX ACTUATOR INSPECTION.)
|
No
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Go to next step.
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||
6*
|
CHECK TO SEE WHETHER MALFUNCTION IS IN AIRFLOW MODE ACTUATOR (SHORT TO GROUND) OR ELSEWHERE
• Disconnect airflow actuator connector.
• Is there voltage of approx. 5 V at A/C amplifier connector (16-pin) terminal 2P (+5 V signal)?
|
Yes
|
Inspect airflow mode actuator, then go to Step 19. (See AIRFLOW MODE ACTUATOR INSPECTION.)
|
No
|
Go to next step.
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7*
|
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO GROUND) IS IN A/C AMPLIFIER OR WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR)
• Disconnect A/C amplifier connector (16-pin).
• Is there continuity between A/C amplifier connector (16-pin) terminal 2P (+5 V signal) and body ground?
|
Yes
|
Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
No
|
Replace A/C amplifier, then go to Step 19.
|
||
8*
|
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN A/C AMPLIFIER OR WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR)
• Disconnect A/C amplifier connector (16-pin) and air mix actuator connector.
• Is there continuity between A/C amplifier connector (16-pin) terminal 2O (potentiometer GND signal) and air mix actuator connector terminal C (L.H.D.) or A (R.H.D.)?
|
Yes
|
Go to next step.
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No
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Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
||
9*
|
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO B+) IS IN A/C AMPLIFIER OR WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR)
• Turn the ignition switch to ON position.
• Test voltage at A/C amplifier connector (16-pin) and terminal 2O (potentiometer GND signal).
• Is voltage approx. 12 V?
|
Yes
|
Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
No
|
Replace A/C amplifier, then go to Step 19.
|
||
10*
|
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR) OR ELSEWHERE
• Turn the ignition switch to ON position.
• Test voltage at air mix actuator connector terminal A (L.H.D.) or C (R.H.D.) (+5 V signal).
• Is voltage approx. 5 V?
|
Yes
|
Go to next step.
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No
|
Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
||
11*
|
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR) OR ELSEWHERE
• Turn the ignition switch to LOCK position.
• Disconnect A/C amplifier connector (16-pin) and air mix actuator connector.
• Is there continuity between A/C amplifier connector (16-pin) terminal 2H (potentiometer input signal) and air mix actuator connector terminal E?
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Yes
|
Go to next step.
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No
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Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
||
12*
|
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO GROUND) IS IN WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR) OR ELSEWHERE
• Is there continuity between A/C amplifier connector (16-pin) terminal 2H (potentiometer input signal) and ground?
|
Yes
|
Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
No
|
Go to next step.
|
||
13*
|
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO B+) IS IN WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR) OR ELSEWHERE
• Turn the ignition switch to ON position.
• Test voltage at A/C amplifier connector (16-pin) terminal 2H (potentiometer input signal).
• Is voltage approx. 12 V?
|
Yes
|
Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
No
|
Go to next step.
|
||
14*
|
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN A/C AMPLIFIER AND AIR MIX ACTUATOR) OR ELSEWHERE
• Turn the ignition switch to LOCK position.
• Is there continuity between following A/C amplifier connector (16-PIN, 24-pin) terminals and air mix actuator connector terminals?
|
Yes
|
Go to next step.
|
No
|
Repair wiring harness between A/C amplifier and air mix actuator, then go to Step 19.
|
||
15
|
INSPECT A/C UNIT AIR MIX ACTUATOR LINK AND CRANK
• Is there grease on the link and crank?
|
Yes
|
Go to next step.
|
No
|
Apply grease, then go to Step 19.
|
||
16
|
INSPECT AIR MIX ACTUATOR
• Inspect air mix actuator.
• Is it normal?
|
Yes
|
Go to next step.
|
No
|
Replace air mix actuator, then go to Step 19. (See AIR MIX ACTUATOR REMOVAL/INSTALLATION.)
|
||
17
|
VERIFY THAT A/C UNIT AIR MIX DOORS DO NOT HAVE ANY FOREIGN MATERIAL OR OBSTRUCTION
• Is there any foreign material or obstructions on any A/C unit door?
|
Yes
|
Remove material/obstruction, then go to Step 19.
|
No
|
Go to next step.
|
||
18
|
INSPECT A/C UNIT AIR MIX DOORS
• Are all doors within A/C unit securely and properly positioned?
• Inspect A/C unit doors.
• Are they normal?
|
Yes
|
Replace A/C amplifier, then go to next step.
(Malfunction in A/C amplifier temperature control lever circuit)
|
No
|
Replace or install door(s) in proper position, then go to next step.
|
||
19
|
CONFIRM THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR
• Does temperature change when operating temperature control dial?
|
Yes
|
Troubleshooting completed.
Explain repairs to customer.
|
No
|
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.
|