Do me a favor guys and look at your radiator cooling fans for me. I am trying to figure something out.

My Grand Cherokee Overland has a HYDRAULIC FAN! Got damn lines coming from the damn power steering pump!

I'm trying to figure out if this is a 4.7 thing, a 4.7 H.O. thing, a Jeep GC only thing, or a Jeep GC Overland H.O. thing.

This is what I've found out so far in researching over the 'net & Jeep sites.

The fan speed is controlled by the PCM and is a Pulse Width Modulated signal to the solenoid. The PCM controls fan speed based on four different conditions...
1. Engine Coolant Temperature
2. Transmission Oil Temperature
3. Battery Temperature
4. A/C System Pressure

Also, for any REAL mechanic types (I'm just the shade tree type), what are the advantages (if any) and disadvantages (besides the obvious fluid leak means fan don't spin) of this setup as opposed to a conventional clutch type of an e-fan?

Well on my 4.7L Magnum, its just the standard clutch fan, no hydraulic lines, just belt driven.

Yeah, finding out it's a 4.7 (standard & H.O.) in a Jeep GC thing to address an issue.

I got a better thread going in the Jeep section, interesting reading.

https://dodgeforum.com/forum/jeeps/1...ml#post1494169

oh ok...good deal then Thanks for the nice read and some good info... I guess ya learn something everyday