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Symptom:
TURN SIGNAL SWITCH INPUT OPEN
When Monitored and Set Condition:
TURN SIGNAL SWITCH INPUT OPEN
When Monitored: Ignition on.
Set Condition: When voltage is below 4.8 volts.
POSSIBLE CAUSES
INTERMITTENT CONDITION
MULTIFUNCTION SWITCH
TURN SIGNAL SWITCH MUX CIRCUIT OPEN
MULTIFUNCTION SWITCH MUX RETURN CIRCUIT OPEN
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, clear all BCM DTC's.
Actuate the turn signals.
With the DRBIIIt, read the DTC information.
Does the DRBIIItread: Turn Signal Switch Input Open?All
Ye s®Go To 2
No®The condition that caused the symptom is currently not present.
Inspect the related wiring for a possible intermittent condition.
Look for any chafed, pierced,pinched, or partially broken wires.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Disconnect the Multifunction Switch harness connector.
Connect a jumper wire between the Turn Signal Switch MUX circuit and the
Multifunction Switch MUX Return circuit in the Multifunction Switch connector.
Turn the ignition on.
With the DRBIIIt, read the Multifunction Switch voltage.
Is the display voltage below 0.5 volts?All
Ye s®Replace the Multifunction Switch.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 3
508
EXTERIOR LIGHTING
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TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Body Control Module harness connector.
Disconnect the Multifunction Switch harness connector.
Measure the resistance of the Turn Signal Switch MUX circuit from the Body Control
Module connector to the Multifunction Switch harness connector.
Is the resistance above 5.0 ohms?All
Ye s®Repair the Turn Signal Switch MUX circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
4 Turn the ignition off.
Disconnect the Body Control Module harness connector.
Disconnect the Multifunction Switch harness connector.
Measure the resistance of the Multifunction Switch MUX Return circuit from the
Body Control Module connector to the Multifunction Switch harness connector.
Is the resistance above 5.0 ohms?All
Ye s®Repair the Multifunction Switch MUX Return circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
509
EXTERIOR LIGHTING
TURN SIGNAL SWITCH INPUT OPEN ÐContinued
Page 539 of 4284

Symptom:
TURN SIGNAL SWITCH INPUT SHORT
When Monitored and Set Condition:
TURN SIGNAL SWITCH INPUT SHORT
When Monitored: Ignition on.
Set Condition: When Input voltage falls below 0.196 volts for 62.5 msec..
POSSIBLE CAUSES
INTERMITTENT CONDITION
MULTIFUNCTION SWITCH
TURN SIGNAL SWITCH MUX CIRCUIT SHORT TO GROUND
TURN SIGNAL SWITCH MUX SHORT TO MUX RETURN CIRCUIT.
MULTIFUNCTION SWITCH MUX RETURN CIRCUIT SHORT TO GROUND
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, clear all BCM DTC's.
Actuate the Turn Signals on.
With the DRBIIIt, read the DTC information.
Does the DRBIIItread: Turn Signal Switch Input Short?All
Ye s®Go To 2
No®The condition that caused the symptom is currently not present.
Inspect the related wiring for a possible intermittent condition.
Look for any chafed, pierced,pinched, or partially broken wires.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Disconnect the Multifunction Switch harness connector.
Turn the ignition on.
With the DRBIIIt, read the Multifunction Switch voltage.
Is the voltage above 4.8 volts?All
Ye s®Replace the Multifunction Switch.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 3
3 Turn the ignition off.
Disconnect the Body Control Module harness connector.
Disconnect the Multifunction Switch harness connector.
Measure the resistance between the Turn Signal Switch MUX circuit and ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Turn Signal Switch MUX circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
510
EXTERIOR LIGHTING
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TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Body Control Module harness connector.
Disconnect the Multifunction Switch harness connector.
Measure the resistance between the Multifunction Switch MUX Return circuit and
the Turn Signal Switch MUX circuit.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Turn Signal Switch MUX circuit for a short to the
Multifunction Switch MUX Return circuit.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 5
5 Turn the ignition off.
Disconnect the Body Control Module harness connector.
Disconnect the Multifunction Switch harness connector.
Measure the resistance between the Multifunction Switch MUX Return circuit and
ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Multifunction Switch MUX Return circuit for a short
to ground.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
511
EXTERIOR LIGHTING
TURN SIGNAL SWITCH INPUT SHORT ÐContinued
Page 541 of 4284

Symptom List:
A/C FAULT (ACTIVE) - MANUAL A/C
CHECKSUM FAILURE (ACTIVE) - MANUAL A/C
POWER FAULT (ACTIVE) - MANUAL A/C
REAR DEFOG FAILURE (ACTIVE) - MAN A/C
RECIRCULATION FAULT (ACTIVE) - MANUAL A/C
UNKNOWN FAULT DETECTED (ACTIVE) - MANUAL A/C
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be A/C FAULT (ACTIVE) - MANUAL
A/C.
When Monitored and Set Condition:
A/C FAULT (ACTIVE) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C switch stays closed for 10 minutes.
CHECKSUM FAILURE (ACTIVE) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the calibrated check sum does not match the stored
value.
POWER FAULT (ACTIVE) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Power switch stays closed for 10 minutes.
REAR DEFOG FAILURE (ACTIVE) - MAN A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Rear Window Defogger switch stays closed for 10
minutes.
RECIRCULATION FAULT (ACTIVE) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Recirc switch stays closed for 10 minutes.
UNKNOWN FAULT DETECTED (ACTIVE) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Cotrol Module detects an internal
fault.
512
HEATING & A/C
Page 542 of 4284
POSSIBLE CAUSES
A/C - HEATER CONTROL MODULE
TEST ACTION APPLICABILITY
1 View repairAll
Repair
Replace the A/C - Heater Control Module in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
513
HEATING & A/C
A/C FAULT (ACTIVE) - MANUAL A/C ÐContinued
Page 543 of 4284

Symptom List:
A/C FAULT (STORED) - MANUAL A/C
BACKLIGHT DIMMING RX FAILURE (STORED) - MANUAL A/C
BLEND OVERCURRENT (STORED) - MANUAL A/C
CHECKSUM FAILURE (STORED) - MANUAL A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN
(STORED) - MANUAL A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT
(STORED) - MANUAL A/C
LOOPBACK FAILURE (STORED) - MANUAL A/C
LOOPBACK TEST FAILURE (STORED) - MANUAL A/C
MODE OVERCURRENT (STORED) - MANUAL A/C
NO BCM MESSAGE RECEIVED (STORED) - MANUAL A/C
NO PCM MESSAGE RECEIVED (STORED) - MANUAL A/C
PCM COMMUNICATION FAILURE (STORED) - MANUAL A/C
POWER FAULT (STORED) - MANUAL A/C
REAR BLEND OVERCURRENT (STORED) - MANUAL A/C
REAR BLEND POT CIRCUIT OPEN (STORED) - MANUAL A/C
REAR BLEND POT CIRCUIT SHORT (STORED) - MANUAL A/C
REAR DEFOG FAILURE (STORED) - MANUAL A/C
REAR MODE OVERCURRENT (STORED) - MANUAL A/C
RECIRC OVERCURRENT (STORED) - MANUAL A/C
RECIRCULATION FAULT (STORED) - MANUAL A/C
TX FAILURE (STORED) - MANUAL A/C
UNKNOWN FAULT DETECTED (STORED) - MANUAL A/C
VEHICLE ODOMETER FAILURE (STORED) - MANUAL A/C
ZONE OVERCURRENT (STORED) - MANUAL A/C
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be A/C FAULT (STORED) - MANUAL
A/C.
When Monitored and Set Condition:
A/C FAULT (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C switch stays closed for 10 minutes.
BACKLIGHT DIMMING RX FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: If the A/C - Heater Control Module does not receive the dimming function
message from the BCM for more than 5 seconds, then the A/C - Heater Control Module
LEDs will default to full brightness and the DTC will set.
514
HEATING & A/C
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BLEND OVERCURRENT (STORED) - MANUAL A/C
When Monitored: When actuator movement is requested.
Set Condition: All (Blend, Mode, Recirc, and Zone) Overcurrent DTCs will set if the A/C
- Heater Control Module detects an excessive current draw on the Common Door Drive
circuit(s).
CHECKSUM FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the calibrated check sum does not match the stored
value.
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN (STORED) - MANUAL
A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Evaporator Temperature Sensor/sensor circuit is
open.
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT (STORED) - MAN-
UAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Evaporator Temperature Sensor/sensor circuit is
shorted low.
LOOPBACK FAILURE (STORED) - MANUAL A/C
When Monitored: When the A/C - Heater Control Module executes an internal loopback
test.
Set Condition: If the A/C - Heater Control Module fails to send a message, or none of the
expected messages arrive for 5 seconds, an internal loopback test is executed. If the
internal loopback test fails, the DTC will set.
LOOPBACK TEST FAILURE (STORED) - MANUAL A/C
When Monitored: When the A/C - Heater Control Module executes an internal loopback
test.
Set Condition: If the A/C - Heater Control Module fails to send a message, or none of the
expected messages arrive for 5 seconds, an internal loopback test is executed. If the
internal loopback test fails, the DTC will set.
MODE OVERCURRENT (STORED) - MANUAL A/C
When Monitored: When actuator movement is requested.
Set Condition: All (Blend, Mode, Recirc, and Zone) Overcurrent DTCs will set if the A/C
- Heater Control Module detects an excessive current draw on the Common Door Drive
circuit(s).
515
HEATING & A/C
A/C FAULT (STORED) - MANUAL A/C ÐContinued