Chevrolet Repair: motorhome fan, temp guage, engine temp

Question
My motorhome with a 454 engine seems to have developed a problem with the high speed cooling fan, it runs much more that it should nearly all of the time on and off on and off even when the engine temp is fine, could you tell me what controls it , it seems like it is getting a false signal to come on.  thanks william  

Answer
Hi William,

I don't know the year of your RV, so I don't know the level of complication under the hood.  If it is newer, you have a temp guage that tells you the engine temp, controlled by that sensor that screws into the cooling system.  However, the fan is controlled by a switch.  This is another screw in device, much like the sensor.  The switch may have a different reading than your guage.  The guage is close, but not neccessarily as accurate as the switch.  So you may think the system is cool enough, and the switch is saying different.  

More possibilities:  The switch is going bad.  The fans will come on automatically, with the AC system.  Is this on?  The computer senses a load, and the fan is on as a result of this.  May be that the engine oil, or the transmission oil is getting too hot.  

I wouldn't worry about this.  As long as the engine is not over cooling.  It is normal to hear the fan kick on for a few seconds, and then off in what may seem like a rapid amount of time.  These RV's are under a heavy load, and proper cooling is very important.  

Enjoy the camping season.

C J S