2015 Peterbilt 579

Mx13. Coolant fan keeps surging likes the air to electric switch is bad. Have replaced it. Sometimes will do it on and off all day, other times will not do it for a month or so. It I flip the fan switch and shut it back off it stops doing it for a while. Had fan clutch checked out and is good. No air leaks. Almost like the computer is telling it to come on. Getting aggravated with it. Any ideas??????

 

No. It’s random. I’m in North Washington right now, no AC on 47° outside. Defroster is not on. Usually when it kicks on for the air conditioning or anything else, the light on the dash comes on. When it’s surging like it is now the light does not come on.

 

Tried to upload a video, but for some reason it won’t let me unless it’s a do YouTube or something first.