Dakota Quad Cab 2WD V8-5.9L VIN Z LDC (2002)
The CTM also provides battery protection to avoid wearing down the battery if the customer leaves the park lamps or headlamps ON for extended
period of time with the ignition OFF. If the park lamps or headlamps remain ON for more than 5 minutes while the ignition is OFF, the headlamps
and park lamps shall be turned OFF and the input causing the lamps to be ON will be ignored until the input is corrected. Once the 5 minute timeout
has extinguished the headlamps and park lamps, any change in the ignition switch, door ajar switches, headlamps switch or park lamp switch will reset
the 5 minute timer and return the headlamps and park lamps to normal operation. A 15 minute timeout is initiated if the ignition is OFF and the
headlamp switch is cycled from OFF to ON (lamp mode).
Heating & A/C System
HEATING & A/C SYSTEM
System Availability
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A Single-Zone HVAC system is available in these vehicles.
System Controls
The Heater Control Module:
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Is fully addressable with the DRB III.
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Communicates over the Programmable Communication Interface Multiplex System (PCI) Bus.
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Controls blower motor operation, providing four blower speeds (Low, M1, M2, & High).
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Controls heated mirror operation (if equipped).
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Controls electronic door actuator operation.
The A/C-Heater Control Module:
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Is fully addressable with the DRB III.
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Communicates over the Programmable Communication Interface Multiplex System (PCI) Bus.
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Uses input from the evaporator temperature sensor to prevent evaporator freeze up while maintaining optimum cooling performance.
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Provides an A/C request to the Powertrain Control Module (PCM) over the PCI Bus when compressor operation is desired.
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Controls blower motor operation, providing four blower speeds (Low, M1, M2, & High).
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Controls heated mirror operation (if equipped).
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Controls electronic door actuator operation.
The Single-Zone HVAC system uses:
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One, two-wire electronic blend door actuator.
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One, two-wire electronic mode door actuator.
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One, two-wire electronic recirculation door actuator.
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A simplified control system for operation of the mode, recirculation, and temperature control actuators provides positive positioning
without the complexity of feedback from position sensors. The A/C - Heater Control Module knows the number of operating actuator
revolutions required for full door travel as well as the number of actuator commutator pulses per revolution. Using these parameters, the
A/C - Heater Control Module runs the actuator for the number of commutator pulses that correspond to the desired door position. To
maintain accuracy, the system recalibrates itself periodically at known zero and full travel conditions.
System Revisions
The 2002 AN and AN84 HVAC system remains mostly carryover from 2001. Revisions to the 2002 HVAC system include:
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New Diagnostic Trouble Codes for a short high on the defog relay control circuit.
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A new System Test called the Actuator Circuit Test.
System Diagnostics
Fault detection is through active and stored Diagnostic Trouble Codes (DTCs)
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DTCs are displayed by the DRB III.
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Active DTCs are those which currently exist in the system. The condition causing the fault must be repaired in order to clear this type of DTC.
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Stored DTCs are those which occurred in the system since the A/C-Heater Control Module received the last "clear diagnostic info" message.
The A/C Cooldown Test:
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is actuated with the DRB III.
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checks A/C system performance based on evaporator temperature sensor input.
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will not run if ambient temperature is below 12.7 °C (55 °F).
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will pass if the evaporator temperature drops 6.7 °C (20 °F) within two minutes of starting the test.
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faults display on the DRB III as test messages only after running the test.
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faults will not display on the DRB III as Diagnostic Trouble Codes.
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will cause the A/C mode switch status indicator to flash while the test is running.
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If the test fails, the status indicator will continue to flash until the test returns passed. It will also prevent the EBL mode switch status
indicator (if equipped) from indicating EBL operating status. However, the EBL mode switch will continue to function in this state.
The HVAC Door Recalibration function:
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is actuated with the DRB III.
