CAUTION: Diagnosis by substituting a component from another vehicle is NOT allowed. Substitution of control modules does not guarantee confirmation of the fault and, in addition, may cause additional faults in the vehicle being tested and/or in the vehicle from which the modules are removed.
1. Visually inspect for obvious signs of damage and system integrity.
Mechanical factors | Electrical Factors |
2. Listen for any unusual noises from the climate control system.
3. Examine the refrigerant system with an ultraviolet lamp for traces of UV sensitive dye to detect leaks.
4. If an obvious cause of a problem you identified or described by the customer is found, resolve it before proceeding to the next steps (if possible).
5. If the cause is not visually obvious, check the climate control module, engine control module (ECM), fuel-fired auxiliary heater and central electrical junction box (CJB) for DTCs and refer to the Index diagnostic trouble codes (DTC).
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