Engine overheating on Cummins ISC 350 Fan not turning

Call Freightliner in Gaffney in the morning with your VIN and ask them if disconnecting should default the fan to high. If true and that did not turn the fan, next thing would be to verify that the fan motor is not frozen up-- can you turn it by hand?

Also, verify with Freightliner that the pump that supplies the fan motor also runs the power steering. Some applications use a separate pump and reservoir for the fan motor.

Do you have a filter in the system-- might change it.

I appreciate the reply's.
I do still have power steering. I tried unplugging the unit but it didn't make a difference. The fan still would not run. I was wondering if it could be a bad fuse or relay. I looked in the Freightliner custom chassis operator manual and was trying to figure out which relay or fuse controls that fan control unit.
Any ideas on what fuse or relay it is? Sorry, not very savvy on the electronic side of things.
I did get a part number off of it. It is a Sauer Danfoss PN# 1090385.

Any help would be much appreciated.

Thanks,

Steve

Verify fluid level.

On most systems (confirm with your chassis maker) disconnecting the wires from the controller defaults the fan to high.

Do you still have power steering? Same pump.