Clint

[ClintBurr]

I have a 2009 Silverado LS short bed regular cab 4X4 with a 4.8L V8.  Whenever I have my heat selection set to both floor and center facing vents (not A/C or defrost) and also have it set to circulate the inside air, my cooling fans continuously come on for about 20 seconds, shut off, and within less than a minute come back on again, and that cycle repeats without stopping and I checked today and my scan tool said the engine was only 189 degrees, and the outside temperature was in the low teens...very cold.  It only seems to happen when these settings are like I said.  If I change the setting to just the floor and the circulate inside air switches to bringing in outside air the fans don't do this.  I can't figure out what's causing it, but I know that since they turn on and off so frequently something is going to fail prematurely from all the on/off switching every minute.  Any ideas?