Page 566 of 4284
TEST ACTION APPLICABILITY
7NOTE: Ensure the voltmeter leads meet the terminals in the connector and
that there is good terminal to wire connection.
NOTE: Ensure the voltmeter leads are connected for positive polarity
Back probe the Evaporator Temperature Sensor Signal circuit between the Evapo-
rator Temperature Sensor harness connector and the A/C - Heater Control Module C1
harness connector.
Turn the ignition on.
Is the voltage below 0.10 volt?All
Ye s®Replace the A/C - Heater Control Module in accordance with the
Service Information. After repair is complete, rerun the Cooldown
Test.
Perform BODY VERIFICATION TEST - VER 1.
No®Repair the high resistance in the Evaporator Temperature Sensor
Signal circuit. After repair is complete, rerun the Cooldown Test.
Perform BODY VERIFICATION TEST - VER 1.
537
HEATING & A/C
COOLDOWN TEST TOO COLD TO START - MANUAL A/C ÐContinued
Page 567 of 4284

Symptom:
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN (ACTIVE)
- MANUAL A/C
When Monitored and Set Condition:
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN (ACTIVE) - MANUAL
A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Evaporator Temperature Sensor/sensor circuit is
open.
POSSIBLE CAUSES
EVAPORATOR TEMPERATURE SENSOR
EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN
SENSOR GROUND CIRCUIT OPEN
A/C - HEATER CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Open the glove box door. Disconnect the glove box door roller latch from each side of
the glove box. Roll the glove box downward toward the floor.
Disconnect the in-line C202 harness connector.
Connect a jumper wire between the Evaporator Temperature Sensor Signal circuit
and the Sensor Ground circuit at the in-line C202 harness connector (HVAC side).
Turn the ignition on.
With the DRBIIItin Sensor Display, read the Evaporator Temperature Sensor
voltage.
Does the DRBIIItdisplay: 0.0 volts?All
Ye s®Check the wiring harness between the in-line C202 harness
connector (plenum side) and the Evap Temp Sensor for an open.
Repair as necessary. If Ok, replace the Evaporator Temperature
Sensor in accordance with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 2
538
HEATING & A/C
Page 568 of 4284

TEST ACTION APPLICABILITY
2 Turn the ignition off.
Disconnect the A/C - Heater Control Module C1 harness connector.
Open the glove box door. Disconnect the glove box door roller latch from each side of
the glove box. Roll the glove box downward toward the floor.
Disconnect the in-line C202 harness connector.
Measure the resistance of the Evaporator Temperature Sensor Signal circuit between
the A/C - Heater Control Module C1 harness connector and the in-line C202 harness
connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 3
No®Repair the Evaporator Temperature Sensor Signal circuit be-
tween the A/C - Heater Control Module C1 harness connector and
the in-line C202 harness connector (HVAC side) for an open.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Disconnect the A/C - Heater Control Module C1 harness connector.
Open the glove box door. Disconnect the glove box door roller latch from each side of
the glove box. Roll the glove box downward toward the floor.
Disconnect the in-line C202 harness connector.
Measure the resistance of the Sensor Ground circuit between the A/C - Heater
Control Module C1 harness connector and the in-line C202 harness connector.
Is the resistance below 5.0 ohms?All
Ye s®Replace the A/C - Heater Control Module in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No®Repair the Sensor Ground circuit between the A/C - Heater
Control Module C1 harness connector and the in-line C202
harness connector (HVAC side) for an open.
Perform BODY VERIFICATION TEST - VER 1.
539
HEATING & A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN (ACTIVE) -
MANUAL A/C Ð
Continued
Page 569 of 4284

Symptom:
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT (AC-
TIVE) - MANUAL A/C
When Monitored and Set Condition:
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT (ACTIVE) - MANUAL
A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Evaporator Temperature Sensor/sensor circuit is
shorted low.
POSSIBLE CAUSES
EVAPORATOR TEMPERATURE SENSOR
EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND
EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO SENSOR GROUND CIR-
CUIT
A/C - HEATER CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Open the glove box door. Disconnect the glove box door roller latch from each side of
the glove box. Roll the glove box downward toward the floor.
Disconnect the in-line C202 harness connector.
Turn the ignition on.
With the DRBIIItin Sensor Display, read the Evaporator Temperature Sensor
voltage.
Does the DRBIIItdisplay: 5.0 volts or greater?All
Ye s®Check the Evap Temp Sensor Signal circuit between the in-line
C202 harness connector (plenum side) and the Evap Temp Sensor
for a short to ground. Repair as necessary. If Ok, replace the
Evaporator Temperature Sensor in accordance with the Service
Info.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 2
540
HEATING & A/C
Page 570 of 4284

TEST ACTION APPLICABILITY
2 Turn the ignition off.
Disconnect the A/C - Heater Control Module C1 harness connector.
Open the glove box door. Disconnect the glove box door roller latch from each side of
the glove box. Roll the glove box downward toward the floor.
Disconnect the in-line C202 harness connector.
Measure the resistance between ground and the Evaporator Temperature Sensor
Signal circuit (HVAC side).
Is the resistance above 10K ohms?All
Ye s®Go To 3
No®Repair the Evaporator Temperature Sensor Signal circuit be-
tween the A/C - Heater Control Module C1 harness connector and
the in-line C202 harness connector (HVAC side) for a short to
ground.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Disconnect the A/C - Heater Control Module C1 harness connector.
Open the glove box door. Disconnect the glove box door roller latch from each side of
the glove box. Roll the glove box downward toward the floor.
Disconnect the in-line C202 harness connector.
Measure the resistance between the Evaporator Temperature Sensor Signal circuit
and the Sensor Ground circuit (HVAC side).
Is the resistance above 10K ohms?All
Ye s®Replace the A/C - Heater Control Module in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No®Repair the Evaporator Temperature Sensor Signal circuit be-
tween the A/C - Heater Control Module C1 harness connector and
the in-line C202 harness connector (HVAC side) for a short to
Sensor Ground.
Perform BODY VERIFICATION TEST - VER 1.
541
HEATING & A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT (ACTIVE) -
MANUAL A/C Ð
Continued
Page 571 of 4284

Symptom List:
FRONT AND REAR BLOWER OUTPUT 1 OPEN
FRONT AND REAR BLOWER OUTPUT 2 OPEN
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be FRONT AND REAR BLOWER
OUTPUT 1 OPEN.
When Monitored and Set Condition:
FRONT AND REAR BLOWER OUTPUT 1 OPEN
When Monitored: Continuously.
Set Condition: If the FCM detects no voltage present on the Front/Rear Blower Motor
Relay Control circuit.
FRONT AND REAR BLOWER OUTPUT 2 OPEN
When Monitored: Continuously.
Set Condition: If the FCM detects no voltage present on the Front/Rear Blower Motor
Relay Control circuit.
POSSIBLE CAUSES
CHECK DTCS
B+ CIRCUIT OPEN
FRONT AND REAR BLOWER RELAYS OPEN
FRONT/REAR BLOWER MOTOR RELAY CONTROL CIRCUIT SHORTED TO GROUND
FRONT/REAR BLOWER MOTOR RELAY CONTROL CIRCUIT OPEN
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
NOTE: If neither DTC will reset or is active, refer to the wiring diagrams
located in the service information to help isolate a possible intermittent
condition.
With the DRB, read the FCM DTC's.
Are both the Front/Rear Blower Output 1 Open and the Front/Rear Blower Output
2 Open DTC's set?All
Ye s®Go To 2
No®Replace the Front Control Module (FCM) in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
542
HEATING & A/C
Page 572 of 4284

TEST ACTION APPLICABILITY
2 Remove either the Front Blower Motor Relay or the Rear Blower Motor Relay, if
equipped, from the IPM.
Using a 12-volt test light connected to ground, probe cavity 86 of the blower relay
connector.
Is the test light illuminated?All
Ye s®Go To 3
No®Check the B+ feed to the Intelligent Power Module (IPM) for an
open. If OK, replace the IPM in accordance with the Service
Information.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Install a substitute relay in place of the existing Front Blower Motor Relay and the
existing Rear Blower Motor Relay, if equipped.
With the DRB, erase DTCs.
Turn the ignition off, wait 30 seconds, then turn the ignition on.
With the DRB, read DTCs.
Did these DTCs reset?All
Ye s®Go To 4
No®Replace the Front Blower Motor Relay and the Rear Blower
Motor Relay, if equipped.
Perform BODY VERIFICATION TEST - VER 1.
4 Turn the ignition off.
Remove the Front Control Module from the IPM.
Remove the Front Blower Motor Relay and the Rear Blower Motor Relay, if equipped,
from the IPM.
Measure the resistance between ground and the Front/Rear Blower Motor Relay
Control circuit (FCM connector cavity 30).
Is the resistance below 5.0 ohms?All
Ye s®Replace the Intelligent Power Module (IPM) in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 5
5 Turn the ignition off.
Remove the Front Control Module from the IPM.
Remove the Front Blower Motor Relay from the IPM.
Measure the resistance of the Front/Rear Blower Motor Relay Control circuit
between the FCM connector cavity 30 and the Front Blower Motor Relay connector
cavity 85.
Is the resistance below 5.0 ohms?All
Ye s®Replace the Front Control Module (FCM) in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Intelligent Power Module (IPM) in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
543
HEATING & A/C
FRONT AND REAR BLOWER OUTPUT 1 OPEN ÐContinued
Page 573 of 4284

Symptom List:
FRONT AND REAR BLOWER OUTPUT 1 SHORT TO BATT
FRONT AND REAR BLOWER OUTPUT 2 SHORT TO BATT
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be FRONT AND REAR BLOWER
OUTPUT 1 SHORT TO BATT.
When Monitored and Set Condition:
FRONT AND REAR BLOWER OUTPUT 1 SHORT TO BATT
When Monitored: With the ignition on.
Set Condition: The FCM detects excessive current when attempting to close the Front/
Rear Blower Motor Relays.
FRONT AND REAR BLOWER OUTPUT 2 SHORT TO BATT
When Monitored: With the ignition on.
Set Condition: The FCM detects excessive current when attempting to close the Front/
Rear Blower Motor Relays.
POSSIBLE CAUSES
CHECK DTCS
FRONT BLOWER MOTOR RELAY SHORTED
REAR BLOWER MOTOR RELAY SHORTED
FRONT/REAR BLOWER MOTOR RELAY CONTROL CIRCUIT SHORTED TO BATTERY
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
NOTE: If neither DTC will reset or is active, refer to the wiring diagrams
located in the service information to help isolate a possible intermittent
condition.
With the DRB, read the FCM DTC's.
Are both of these DTCs set?All
Ye s®Go To 2
No®Replace the Front Control Module (FCM) in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
544
HEATING & A/C