Fan clutch was stuck engaged in thirty degree temperatures

Good afternoon,

The clutch is controlled by the PCM. Once it sees the signal from the coolant sensor, it will turn on or off the clutch depending on load and temperature.

There was a TSB on updating the program for the fan clutch.

I attached the TSB and a wiring diagram for you to view.

Roy

NUMBER: 07-003-10

GROUP: Cooling

DATE: September 09, 2010

SUBJECT:
High Coolant Temperatures On Vehicles Equipped With Snow Plows

OVERVIEW:
This bulletin provides information on how to program the Engine Control Module (ECM) to force the fan clutch to fully engage at all operating conditions

MODELS:

2007 - 2010 DC/DM Ram 3500/4500/5500 Cab Chassis Trucks 2011 DD/DP Ram 3500/4500/5500 Cab Chassis Trucks

NOTE:
This bulletin applies to vehicles equipped with the 6.7L Cummins Diesel engine (Sales Code ETJ)

DISCUSSION:

Customers that operate their vehicle with a snowplow attached to the vehicle may cause the airflow passing through the radiator to be disrupted resulting in higher than normal engine temperatures The 6 7L Cummins ECM is equipped with software that can fully engage the fan clutch to allow an increase of airflow through the radiator Customers can initiate the fan clutch operation by performing the following button sequence

NOTE:
2007 early 2009 models were not originally equipped with the fan clutch software however, recently released software does include this enhancement Ensure that the ECM software is at the latest level and if not, flash the ECM Refer to Service Bulletin 18-020-10 for additional information

1. Turn the ignition key to the run position or start the truck

2. Simultaneously press and release the Cruise Control "Cancel" button/lever and the "Exhaust Brake" button. Repeat this sequence four times within five seconds. The chime will sound twice as an audible indicator that the function is engaged

3. To disable the function, repeat the same procedure The chime will sound four times as an audible indicator that the function is disengaged

NOTE:
Customer's should be made aware that an increase in fan noise and a decrease in fuel economy may result when using this feature.

POLICY:
Information Only

Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.