Tech Tip: RAM 2500 A/C inoperable

Nov. 18, 2021

The truck was brought to the shop because the A/C was blowing warm air.

Related To:

Vehicle: 2006 Dodge RAM 2500, 2WD, L6-5.9L DSL Turbo, VIN C, Automatic Transmission

Mileage: 168,009

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.

Confirmed Repair:

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!

About the Author

Richard Diegle | Senior Automotive Editor for ALLDATA

Rich Diegle has been in the automotive industry since 1978. After graduating from a local community college, he began working at a Nissan dealership as a used car technician. Since then, he’s worked as a Nissan and ASE master automotive technician, shop owner, marketing copywriter, automotive editor, public relations manager, instructor, ALLDATA Tech-Assist team manager, and a senior automotive editor.