RAM 3500 Truck 4WD L6-5.9L DSL Turbo VIN C (2002)
Control Assembly: Testing and Inspection
Satisfactory heater and air conditioner performance depends upon proper operation and adjustment of all operating controls and refrigeration system
components. For circuit descriptions and diagrams. These inspections, tests, and adjustments should be used to locate the cause of a malfunction.
Operation must be tested as described in the following sequence:
1. Inspect and adjust the serpentine drive belt.
2. Start the engine and hold the idle speed at 1,300 rpm.
3. On vehicles with air conditioning, turn the temperature control knob to the extreme counter clockwise (Cool) position, and set the mode control
switch knob to the Bi-Level (A/C) position. The outside (recirculation) air door should be open to outside air. If not OK, (Refer to HEATING &
AIR CONDITIONING - DIAGNOSIS AND TESTING - VACUUM SYSTEM See: Testing and Inspection/Symptom Related Diagnostic
Procedures/Vacuum Control System Diagnosis).
4. Open the vehicle windows. Test the blower motor operation in all speeds. If not OK, (Refer to HEATING & AIR CONDITIONING - BLOWER
MOTOR - DIAGNOSIS AND TESTING See: Blower Motor/Testing and Inspection).
5. On vehicles with air conditioning, the compressor should be running and the air conditioning system in operation unless the ambient air
temperature is below about -1 °C (30 °F). If not OK, (Refer to HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING - A/C
PERFORMANCE See: Testing and Inspection/Symptom Related Diagnostic Procedures/A/C Performance Test).
6. Check the mode control switch operation. The heater and air conditioner systems should respond as described in the owner's manual in the vehicle
glove box to each mode selected. Reduce the engine speed to normal idle. The vacuum will be high at low idle and the vacuum actuators should
respond quickly. If not OK, (Refer to HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING - VACUUM SYSTEM See: Testing
and Inspection/Symptom Related Diagnostic Procedures/Vacuum Control System Diagnosis).
7. If the vacuum tests, and the electrical component and circuit tests reveal no problems, disassemble the HVAC housing to inspect for mechanical
misalignment or binding of the mode doors (Refer to HEATING & AIR CONDITIONING/HVAC HOUSING - DISASSEMBLY See: Housing
Assembly HVAC/Service and Repair/Overhaul).