Ev fan clutch

I have a 2008 Chevy trailblazer 4.2. I seen in my alldata gas electro vicious fan clutch but see no wires or no bi directional controls on my snap on versus edge. Someone said that gm in 2008 or 2009 switched to a thermal fan clutch. I looked online at AZ and one they showed had no wires. I guess mine is thermal. Alldata must be wrong.. Any idea?

From what I recall, the harness isn't easy to see, but it's there. It leads to a hub at the base of the fan clutch that is the electo-part of the electro-viscous clutch.
I seem to recall from some parasitic draw testing that I've done in the past that it is controlled by one of two solid state relays in the underhood fuse block, the other being for the headlamps.

Thanks Noah for reply. I was told gm went to a thermal clutch fan in 2008. Mine has no wires and AZ shows a thermal fan clutch for my 2008 trailblazer 4 2. Also I looked at the pcm pinout diagram for my truck on my alldata and the pins associated with electro viscious fan clutch say not used. I'm thinking it is a thermal fan clutch. Here is the gm oe part number 25816289.

Well sir, provided with that evidence I believe that I was incorrect. I know most of them I had worked on had the electronic version.
Much better for you

Thanhs Noah. I just didn't know gm changed over. My alldata showed it as electro viscious clutch but pcm pin out diagram showed those pins listed in clutch electrical diagram as not used. Then no special function bi directional controls. Still little difficult to change. Thank you for your time.