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HVAC DTC Troubleshooting: 1
DTC indicator 1: An Open in the Air Mix Control Motor Circuit
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1. |
Problem verification:
Problem verification
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?1. |
Turn the ignition switch to LOCK (0) and then back to ON (II). |
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Is DTC 1 indicated?
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Intermittent failure. Check for loose wires or poor connections on the air mix control motor circuit.? |
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2. |
Open wire check (AMD-P DR/AMD-P line):
Open wire check (AMD-P DR/AMD-P line)
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?1. |
Turn the ignition switch to LOCK (0). |
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?2. |
Disconnect the following connectors.
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?3. |
Check for continuity between test points 1 and 2.
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Test condition |
IG LOCK (0) |
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HVAC control unit 32P connector: disconnected |
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Air mix control motor 7P connector: disconnected |
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Test circuit |
AMD-P DR/AMD-P |
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Test point 1 |
HVAC control unit 32P connector No. 13 (GRY) |
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Test point 2 |
Air mix control motor 7P connector No. 2 (GRY) | |
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Is there continuity?
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The AMD-P DR/AMD-P wire is not open. Go to step 3. |
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Repair an open in the wire between the HVAC control unit and the air mix control motor.? |
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3. |
Open wire check (SENSOR COM/SENS-COM line):
Open wire check (SENSOR COM/SENS-COM line)
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?1. |
Check for continuity between test points 1 and 2.
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Test condition |
IG LOCK (0) |
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HVAC control unit 32P connector: disconnected |
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Air mix control motor 7P connector: disconnected |
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Test circuit |
SENSOR COM/SENS-COM |
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Test point 1 |
HVAC control unit 32P connector No. 20 (BLU) |
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Test point 2 |
Air mix control motor 7P connector No. 1 (RED) | |
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Is there continuity?
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The SENSOR COM/SENS-COM wire is not open. Go to step 4. |
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Repair an open in the wire between the HVAC control unit and the air mix control motor.? |
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4. |
Shorted wire check (S 5V/S5V line to AMD-P DR/AMD-P line):
Shorted wire check (S 5V/S5V line to AMD-P DR/AMD-P line)
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?1. |
Check for continuity between test points 1 and 2.
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Test condition |
IG LOCK (0) |
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HVAC control unit 32P connector: disconnected |
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Air mix control motor 7P connector: disconnected |
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Test circuit |
S 5V, AMD-P DR |
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Test point 1 |
HVAC control unit 32P connector No. 13 (GRY) |
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Test point 2 |
HVAC control unit 32P connector No. 16 (BLK) | |
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Is there continuity?
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Repair a short in the wires between the HVAC control unit and the air mix control motor.? |
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The S 5V/S5V wire to AMD-P DR/AMD-P wire are not shorted. Go to step 5. |
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5. |
Air mix control motor internal resistance check (S5V and SENS-COM):
Air mix control motor internal resistance check (S5V and SENS-COM)
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?1. |
Measure the resistance between test points 1 and 2.
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Test condition |
IG LOCK (0) |
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HVAC control unit 32P connector: disconnected |
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Air mix control motor 7P connector: disconnected |
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Test circuit |
S5V, SENS-COM |
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Test point 1 |
Air mix control motor No. 1 |
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Test point 2 |
Air mix control motor No. 3 | |
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Is the resistance 6 k?  1.8 k??
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6. |
Air mix control motor internal resistance check (S 5V and AMD-P DR):
Air mix control motor internal resistance check (S 5V and AMD-P DR)
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?2. |
Connect the battery power and ground to terminals A and B, then reverse the connections.
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Terminal A |
HVAC control unit 32P connector No. 5 (PNK) |
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Terminal B |
HVAC control unit 32P connector No. 6 (LT BLU) | |
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NOTE: Incorrectly applying power and ground to the motor will damage it. Follow the instructions carefully. When the motor stops running, disconnect battery power immediately.
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?3. |
Measure the resistance between test points 1 and 2.
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Test condition |
IG LOCK (0) |
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HVAC control unit 32P connector: disconnected |
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Test circuit |
S 5V, AMD-P DR |
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Test point 1 |
HVAC control unit 32P connector No. 13 (GRY) |
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Test point 2 |
HVAC control unit 32P connector No. 16 (BLK) | |
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NOTE: Continuity between S 5V and AMD-P DR may disappear when the motor is turned to the stop. Usually the HVAC control unit does not turn the motor to the stop.
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Does resistance change between about 0?6 k?  1.8 k?? |