Hi I am having a very annoying problem with the fan of my 08. It will come on often and for long periods of time, sometimes on for 50 miles down the interstate. And it comes on a couple minutes of riding after a cold start. Really hurts fuel economy. The dealer replaced the fan clutch and reflashed the computer. Still does it. I heard about a guy with the same problem on a different forum. ANY NEWS OR HELP?

 

Does it get hot? check the coolant, some radiators have been bad. You do mean the Radiator Fan? the clutch kicking in, makes the sound of a big rig?

 

Well, the radiator has been replaced for the leaking problem and the coolant is good.
Yes I am talking about the radiator fan(they replaced they fan clutch)

 

I wonder if there is a temp sensor or something that is not reading right, giving it a bad reading, casing the fan to turn on???

 

These fans are supposed to engage when engine is cold to increase the load on engine for a quicker warmup. Is it possible a stuck open or defective thermostat might also allow this "feature" to activate going down the highway in colder climates?

 

Mine kicks in almost all the time when I am towing my 39 foot 5th wheel toyhauler. I check my guauges and they are always normal. I really notice it when I am going up a grade, but it will also come on when I am on a flat road and once when I was going down hill.