are the fans supposed to be on all the time? i noticed them on when i first started truck and when i put ac on they speed up but when i turn ac off they still run at a slower rate.truck is running cool so no complaints just curious,for some reason i thought they engage only when ac is turned on,thanksbtw truck was not totally cold but had sat for hours

 

electric fans should power on under two circumstances.. 1) A/C on or 2) coolant temp >220 deg

If they are on all the time something is not 'stock'. Perhaps a prior owner wired them up to run constantly to help an overheating tendency.

 

thanks for responding,i put these fans on a couple years ago and yes they are aftermarket but plugged right in,recently changed coolant temp sensor and just wondered if that changed anything.also changed viscous fan clutch,just thought maybe cause engine was still warm they engaged,engine by no means was 212 as it sat for hours.maybe something electrical?thought maybe cause compressor button is always on or the slide for the fan might be doing something funny?just started her this am and they are turning,played with switch but they stayed on and engage faster with ac on,anyway not complaining,truck is running cool so...