Description:
If the truck has a normally closed A/C High Pressure switch installed and connected to the ECM, and the ECM is wired to run the cooling fan, then the A/C Pressure Switch Fan-On Time can be programmed to prevent excessive cycling of the cooling fan clutch. This parameter has no effect on any other Cooling Fan-On condition, only when the cooling fan is turned on by high A/C Pressure. Programming the A/C Pressure Switch Fan-On Time to 0 (zero) disables this feature and the ECM will not monitor this input.
Available:
All electronically controlled on-highway engines covered in this handbook
Range:
Advantages:
The A/C Pressure Switch Fan-On Time can reduce the amount of fan cycling and increase fan clutch life.
Recommendations:
Caterpillar recommends a setting of 60 to 120 seconds with C-135 refrigerant.