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??????