NO.4 NO TEMPERATURE CONTROL WITH A/C AMPLIFIER [MANUAL AIR CONDITIONER]
id0703c2803400
4
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No temperature control with A/C amplifier.
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DESCRIPTION
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• Temperature does not change with operating temperature control dial.
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POSSIBLE CAUSE
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• Air mix actuator (+5 V signal) system malfunction (Steps 3—7, 10)
• A/C amplifier (potentiometer GND signal) system malfunction (Steps 8, 9)
• Air mix actuator (potentiometer input signal) system malfunction (Steps 11—13)
• Air mix actuator (potentiometer GND signal, motor drive signal) system malfunction (Step 14)
• Air mix actuator system malfunction (Steps 15, 16)
• A/C unit air mix door malfunction (Steps 17, 18)
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Diagnostic procedure
STEP |
INSPECTION |
ACTION |
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1
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INSPECT COOLANT TEMPERATURE
• Is coolant sufficiently warmed up?
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Yes
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Go to the next step.
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No
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Warm engine up, then go to Step 19.
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2
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CHECK CIRCUITS COMMON TO BOTH AIR MIX ACTUATOR AND AIRFLOW MODE ACTUATOR
• Does airflow mode change when operating airflow mode selector switch?
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Yes
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Go to Step 10.
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No
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Go to the next step.
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3
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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.)
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Yes
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Go to the 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*
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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 2N (potentiometer GND 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 the 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 2N (potentiometer GND signal)?
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Yes
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Inspect air mix actuator, then go to Step 19.
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No
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Go to the next step.
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6*
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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 2N (potentiometer GND signal)?
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Yes
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Inspect airflow mode actuator, then go to Step 19.
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No
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Go to the next step.
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7*
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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 2N (potentiometer GND 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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Replace A/C amplifier, then go to Step 19.
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8*
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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 2P (+5 V signal) and air mix actuator connector terminal C?
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Yes
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Go to the 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.
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9*
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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 2P (+5 V signal).
• Is voltage approx. 12 V?
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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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Replace A/C amplifier, then go to Step 19.
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10*
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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 (potentiometer GND signal).
• Is voltage approx. 5 V?
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Yes
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Go to the 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.
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11*
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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 2D (potentiometer input signal) and air mix actuator connector terminal E?
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Yes
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Go to the 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.
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12*
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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 2D (potentiometer input signal) and ground?
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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 the next step.
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13*
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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 2D (potentiometer input signal).
• Is voltage approx. 12 V?
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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 the next step.
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14*
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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?
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Yes
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Go to the 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.
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15
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INSPECT A/C UNIT AIR MIX ACTUATOR LINK AND CRANK
• Is there grease on the link and crank?
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Yes
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Go to the next step.
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No
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Apply grease, then go to Step 19.
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16
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INSPECT AIR MIX ACTUATOR
• Inspect air mix actuator.
• Is it normal?
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Yes
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Go to the next step.
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No
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Replace air mix actuator, then go to Step 19.
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17
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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?
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Yes
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Remove material/obstruction, then go to Step 19.
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No
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Go to the next step.
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18
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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?
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Yes
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Replace A/C amplifier, then go to the next step.
(Malfunction in A/C amplifier temperature control lever circuit)
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No
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Replace or install door(s) in proper position, then go to the next step.
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19
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CONFIRM THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR
• Does temperature change when operating temperature control dial?
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Yes
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Troubleshooting completed.
Explain repairs to customer.
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No
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Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.
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