Content .. 2003 2004 2005 2006 ..

Dodge Ram Truck 1500-2500-3500. Manual - part 2005

BLEND OVERCURRENT (DUAL-ZONE)

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HVAC - ELECTRICAL DIAGNOSTICS

DR/DH

BLEND OVERCURRENT (DUAL-ZONE) (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 all Actuator Circuit Test faults before diagnosing Overcurrent DTCs.

The A/C Heater Control monitors the door driver circuits during actuator operation for shorts to ground, shorts to
battery, and shorts to other door driver circuits. If detected, the A/C Heater Control reports these types of faults as
Overcurrent DTCs. It is important to note that Overcurrent DTCs do not indicate where or what type of short is
present and that additional system testing is necessary to provide more details about the reported fault.

•

When Monitored:
When actuator movement is requested.

•

Set Condition:
If the A/C Heater Control detects an excessive current draw on any of the door driver circuits while attempting
to drive the Passenger Blend Door Actuator. Note that only one overcurrent DTC can set per ignition cycle.

Possible Causes

(C32) RECIRCULATION DOOR DRIVER CIRCUIT / (C61) BLEND DOOR DRIVER CIRCUIT / (C801) MODE
DOOR 1 DRIVER CIRCUIT / (C29) MODE DOOR 2 DRIVER CIRCUIT / (C33) PASSENGER BLEND DOOR
DRIVER CIRCUIT SHORTED TO GROUND

DRIVER BLEND DOOR ACTUATOR / PASSENGER BLEND DOOR ACTUATOR / MODE DOOR ACTUATOR 1 /
MODE DOOR ACTUATOR 2 / RECIRCULATION DOOR ACTUATOR

A/C HEATER CONTROL

NOTE: This DTC must be active for the result 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

RUN THE ACTUATOR CIRCUIT TEST

Turn the ignition on.

With the DRBIII

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

pletion before proceeding.

Does the DRBIII

display any Actuator Circuit Test fault messages?

Yes

>> Diagnose and repair the fault(s). Refer to *ACTUATOR CIRCUIT TEST DIAGNOSTICS (DUAL-ZONE) in

this section.

>> Go To 2

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HVAC - ELECTRICAL DIAGNOSTICS

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BLEND OVERCURRENT (DUAL-ZONE) (CONTINUED)

CHECK THE (C32) RECIRCULATION DOOR DRIVER CIRCUIT FOR A SHORT TO THE (C61) BLEND
DOOR DRIVER CIRCUIT, THE (C801) MODE DOOR 1 DRIVER CIRCUIT, THE (C29) MODE DOOR 2
DRIVER CIRCUIT, & THE (C33) PASSENGER BLEND DOOR DRIVER CIRCUIT

Turn the ignition off.

Disconnect the A/C Heater Control C1 harness connector.

Measure the resistance between the (C32) Recirculation Door Driver
circuit and the (C61) Blend Door Driver circuit, the (C801) Mode Door
1 Driver circuit, the (C29) Mode Door 2 Driver circuit, and the (C33)
Passenger Blend Door Driver circuit in the A/C Heater Control C1 har-
ness connector.

Is the resistance below 10k ohms on any of the circuits?

Yes

>> Repair all circuits with a resistance below 10k ohms for a

short to the (C32) Recirculation Door Driver circuit.

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

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).

>> Go To 3

CHECK THE (C61) BLEND DOOR DRIVER CIRCUIT FOR A SHORT TO THE (C801) MODE DOOR 1
DRIVER CIRCUIT, THE (C29) MODE DOOR 2 DRIVER CIRCUIT, & THE (C33) PASSENGER BLEND DOOR
DRIVER CIRCUIT

Measure the resistance between the (C61) Blend Door Driver circuit
and the (C801) Mode Door 1 Driver circuit, the (C29) Mode Door 2
Driver circuit, and, the (C33) Passenger Blend Door Driver circuit in
the A/C Heater Control C1 harness connector.

Is the resistance below 10k ohms on any of the circuits?

Yes

>> Repair all circuits with a resistance below 10k ohms for a

short to the (C61) Blend Door Driver circuit.

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

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).

>> Go To 4

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HVAC - ELECTRICAL DIAGNOSTICS

DR/DH

BLEND OVERCURRENT (DUAL-ZONE) (CONTINUED)

CHECK THE (C801) MODE DOOR 1 DRIVER CIRCUIT FOR A SHORT TO THE (C29) MODE DOOR 2
DRIVER CIRCUIT & THE (C33) PASSENGER BLEND DOOR DRIVER CIRCUIT

Measure the resistance between the (C801) Mode Door 1 Driver cir-
cuit and the (C29) Mode Door 2 Driver circuit, and the (C33) Passen-
ger Blend Door Driver circuit in the A/C Heater Control C1 harness
connector.

Is the resistance below 10k ohms on any of the circuits?

Yes

>> Repair all circuits with a resistance below 10k ohms for a

short to the (C801) Mode Door 1 Driver circuit.

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

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).

>> Go To 5

CHECK THE RESISTANCE BETWEEN THE (C29) MODE DOOR 2 DRIVER CIRCUIT & THE (C33)
PASSENGER BLEND DOOR DRIVER CIRCUIT

Measure the resistance between the (C29) Mode Door 2 Driver circuit
and the (C33) Passenger Blend Door Driver circuit in the A/C Heater
Control C1 harness connector.

Is the resistance below 10k ohms?

Yes

>> Repair the (C33) Passenger Blend Door Driver circuit for a

short to the (C29) Mode Door 2 Driver circuit.

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

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).

>> Go To 6

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HVAC - ELECTRICAL DIAGNOSTICS

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Content .. 2003 2004 2005 2006 ..