How to disconnect coolant fan

Okay. Well in morning I will pull that air line off at the firewall valve and check to see if any air is coming out in the first place. Just thought about that.
If there is, I will shut down and blow air in line and see if it leaks.

 

Well I changed temp sensor on back of engine passenger side , no change.
I pulled airline to fan. No air coming out. Blew air in, fan shut off.
Shut off engine and sensor on the air valve clicked and air blew out line then stopped for an instant then clicked and blew a bit of air and shut off air entirely .
So is that switch operating correctly
?

 

So any ideas why I. My software I have fan switch set to on ?
I have no fan switch.
Plus this just happened so I know that setting either could not been already set on or it actually does nothing and don't matter.
But it set to on in software

 

Good news is I remembered I knew someone with the basic paccar software. Good enough for this job.
He found the fan switch had somehow been set to on. He turned it off and problem solved. No idea how it turned itself to on. I don't have a fan switch in my truck "Goodysnap, post: 11678395, member: 200878"]It sounds like the fan solenoid is functioning as it should as is the clutch. Sounds like you might be in for a trip to the stealership after all.

Something is telling the fan to come on and stay on.[/QUOTE]

 

Problem not solved. Just another 150 bucks wasted .
Some how the ecm keeps switching fan to on. Mechanic turned it to off and it stayed that way while running. I started it up later and fan came on. I shut down, restarted fan stayed off.
This morning I start it up and fan back on.
Thinking maybe filing bankruptcy to get rid of this paccar crap might be the best option.

 

Came back on this morning but after running a few minutes it's off. Guess that is normal .