Dodge Repair Questions? Ask a Mechanic for Answers ASAP
Hello, when you turn the ac system on, the compressor engages? Do the fans come on when the engine reaches normal operating temperature with the ac off? No warning lights on? If you apply power and ground to the fans will they operate?
DIAGNOSIS AND TESTING - RADIATOR FAN CONTROLFan control is accomplished three ways. The fan runs when the air conditioning pressure reaches a set pressure, refer to RADIATOR FAN OPERATION chart. In addition to this control, the fan is turned on by the temperature of the coolant which is sensed by the coolant temperature sensor which sends the message to the Powertrain Control Module (PCM). The PCM turns on the fan through a fan relay. On models equipped with automatic transmission, a transmission fluid thermister may have some influences on fan operation. See Wiring Diagrams Manual for circuity and diagnostics provided.The Powertrain Control Module (PCM) provides fan control for the following conditions:
it doesnt list a chart for the 3.5 engine, the pcm controls the operation of the low and high speed fan operation. Since the fans do operate on their own for engine temperature, A diagnostic check for codes with a scan tool should be done to see if there is a fault with an ac pressure sensor or ac input fault. If the scan tool can look at live sensor data, it can be used to see if the ac demand is showing that it is on to tell the pcm to operate the fans and if the fans are being commanded on or not. If it is being commaned, then it would be a question if it is a low or high fan speed that is not working and which relay to check which operate the fan speed.
Then it has to be an issue with the PCM control of the fan system. A diagnostic scan tool would be needed to check for codes and see if you can command the fans on using the scan tool to eliminate a wiring issue or other control system fault.
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