Dodge Ram Truck 1500-2500-3500. Manual — part 2014

EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORTED (CONTINUED)

2.

CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off.

Disconnect the A/C Heater Control C1 harness connector.

Measure the resistance of the (C21) Evaporator Temperature Sensor
Signal circuit between ground and the A/C Heater Control C1 harness
connector.

Is the resistance below 10k ohms?

Yes

>> Repair the (C21) Evaporator Temperature Sensor Signal

circuit for a short to ground.

Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
-

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).

No

>> Go To 3

3.

CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO (C121)
SENSOR GROUND CIRCUIT

Measure the resistance between the (C21) Evaporator Temperature
Sensor Signal circuit and the (C121) Sensor Ground circuit in the A/C
Heater Control C1 harness connector.

Is the resistance below 10k ohms?

Yes

>> Repair the (C21) Evaporator Temperature Sensor Signal

circuit for a short to the (C121) Sensor Ground circuit.

Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
-

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).

No

>> Replace the A/C Heater Control in accordance with the

Service Information.

Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
-

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT

CONTROL

MODULE

-

DIAGNOSIS

AND

TESTING).

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HVAC - ELECTRICAL DIAGNOSTICS

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LOOPBACK TEST FAILURE

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
When executing an internal loopback test.

•

Set Condition:
If the A/C Heater Control either fails to broadcast a message on the PCI Bus or fails to receive expected
messages from the PCI Bus for 5 seconds it will execute an internal loopback test. This DTC will set if the
internal loopback test fails.

Possible Causes

A/C HEATER CONTROL

NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC
is stored. Refer to HVAC System Test for stored DTC test procedures.

Diagnostic Test

1.

REPLACE THE A/C HEATER CONTROL

Repair

Replace the A/C Heater Control in accordance with the Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING).

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HVAC - ELECTRICAL DIAGNOSTICS

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MODE 1 CALIBRATION FAULT

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HVAC - ELECTRICAL DIAGNOSTICS

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MODE 1 CALIBRATION FAULT (CONTINUED)

For the Manual Temperature Control circuit diagrams (Refer to 24 - HEATING & AIR CONDITIONING - SCHEMAT-
ICS AND DIAGRAMS).

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

NOTE: Diagnose and repair Actuator Circuit Test faults before diagnosing Overcurrent faults and Calibration
faults. Diagnose and repair Overcurrent faults before diagnosing Calibration faults.

The purpose of actuator calibration is to determine the total span of door travel between physical stops. To calibrate
the actuator, the A/C Heater Control first moves the door to its soft stop, and then counts the number of pulses it
takes to move the door to its other stop. An expected range of span is stored in the control’s memory. If the mea-
sured calibration value is not within the expected range, this fault will set.

For vehicles equipped with electric backlight (EBL), running the HVAC Door Recalibration will cause the EBL status
indicator to flash. If recalibration fails, the EBL status indicator will continue to flash until either the system passes
recalibration or the ignition key is cycled. When the EBL status indicator is flashing, it will not indicate EBL operating
status. However, the EBL mode switch will continue to function normally. When the EBL status indicator is flashing,
the A/C status indicator will not function. However, the A/C mode switch will continue to function normally.

For vehicles not equipped with electric backlight (EBL), no status indicator will flash when running the HVAC Door
Recalibration. If recalibration fails, the A/C status indicator will not function, however, the A/C mode switch will con-
tinue to function normally.

•

When Monitored:
When HVAC Door Recalibration is executed.

•

Set Condition:
If the span of mode door 1 is found outside the tolerance.

Possible Causes

(C801) MODE DOOR 1 DRIVER CIRCUIT SHORTED TO GROUND (WILL ALSO SET OVERCURRENT DTCs)

(C801) MODE DOOR 1 DRIVER CIRCUIT SHORTED TO VOLTAGE (WILL ALSO SET OVERCURRENT DTCs)

(C801) MODE DOOR 1 DRIVER CIRCUIT OPEN

(C34) COMMON DOOR DRIVER CIRCUIT OPEN

MODE DOOR ACTUATOR 1 OPEN

MODE DOOR ACTUATOR 1 BROKEN

MODE DOOR 1 BOUND UP

MODE DOOR 1 LINKAGE MISSING, BROKEN

A/C HEATER CONTROL

Diagnostic Test

1.

RUN THE ACTUATOR CIRCUIT TEST

Turn the ignition on.

With the DRBIII

T

in HVAC, select System Tests and then select Actuator Circuit Test. Allow the test to run to com-

pletion before proceeding.

Does the DRBIII

T

display any Actuator Circuit Test fault messages?

Yes

>> Diagnose and repair the fault(s). For Single-Zone HVAC systems, refer to *ACTUATOR CIRCUIT TEST

DIAGNOSTICS (SINGLE-ZONE) in this section. For Dual-Zone HVAC systems, refer to *ACTUATOR
CIRCUIT TEST DIAGNOSTICS (DUAL-ZONE) in this section.

No

>> Go To 2

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HVAC - ELECTRICAL DIAGNOSTICS

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