Re: Radiator Fan
What jp467 and mr bots said. All modern vehicles have all sorts of performance information available in the ECU, but they don't usually make it available to the driver. It seems they don't want to spook folks with too much information.
One of my other cars has a fake oil pressure gauge. The oil pressure sensor is actually just a pressure switch, and if the ECU senses adequate pressure, it makes the oil pressure sensor go through a fake dance like it is really reading the pressure. Less than totally worthless, especially since the car won't tell you it has zero oil pressure except by moving the oil pressure needle to zero. No idiot lights, no alarm, just the fake gauge at zero until the loud knocking starts.
Kudos to Jeep for providing this info, as it can be very useful when trouble shooting problems as these trucks age.