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Topic: Hydraulic fan control - '99 Affinity (Read 1083 times) previous topic - next topic
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Hydraulic fan control - '99 Affinity

I have a '99 Affinity with the Cat C12 motor.  I'm trying to understand if my hydraulic fan is operating correctly or not as I have the classic dust cloud under the rear when driving on dirt roads. 
Here is what I know:

The system has a Sauer Sundstrand wax valve in the radiator in series with a two wire Sauer Sundstrand solenoid valve which control fan speed.
At idle, the fan turns approximately 780 RPM.
There is no power to the solenoid, even with the over the road AC on. (5 amp fuse may be blown but don't know where it is located).
If I jumper 12volts to the solenoid, the fan RPM drops to 190 RPM.
At this point, I don't know if the fan speed increases with either temperature or engine rpm.

My questions are:
1.  Can someone explain how the system is supposed to operate?
2. What is the expected fan RPM at idle?
3. What is Max fan RPM?
4. What is the purpose of the Hydraulic solenoid?
5. where is the 5 amp fuse that is in the hydraulic solenoid circuit.

 Also posting to IRV2
thanks,
Jim