Vehicle: 2006 Dodge RAM 2500, 2WD, L6-5.9L DSL Turbo, VIN C, Automatic Transmission
Problem: The truck was brought to the shop because the A/C was blowing warm air. The customer said it was working fine the day before.
Case Details: The tech noted that the A/C compressor clutch was not engaging. The static A/C system pressures were within specifications, and he found no diagnostic trouble codes. At that point, he called ALLDATA Tech-Assist for some advice.
The Tech-Assist consultant recommended that the technician use a scan tool to monitor the data PIDs that could stop compressor operation, such as: engine coolant temperature, intake air temperature, A/C refrigerant pressure, ambient air temperature, and evaporator temperature.
The tech followed the consultant’s advice and found that the evaporator temperature sensor PID was reading only 1 degree Fahrenheit.
Next, he checked the evaporator temperature sensor electrical circuit. He found that pin 7 on Connector C1 at the control head was slightly pushed out.
Once he repaired and refitted the pin, the evaporator temperature sensor PID readings were back in the correct range. Normal compressor operation was restored, and A/C began cooling as designed. Fixed!