Engine fan runs sometimes on start up even in cold weather. turn on defroster and fan cycles in/out. note: A/C is not hooked up to cause fan to kick in.









2003 2500 5.9 all stock....

 

Maybe the fan clutch going bad?

 

I would check the wires where they run across the brace and by the a/c compressor

 

I hear mine run on cold startup sometimes as well. Always has done that. Not all the time though. Figured it was normal?
As far as when running under a big load, mine rarely kicks in, even grossing close to 20k uphill. And my radiator has most of the fins bent over blocking flow, thanks to my kids a few years ago! It's kinda like having a winter front on all the time, but has caused no problems and the truck runs right at 200deg +/- in all weather.