I just installed a set of factory GMT900 electric fans on my 05 1500HD. Now I have the provisions for factory electric fans, but obviously the HD trucks never had them. I used the LS1fans.com harness for the install.

Now really I am wired exactly as a factory 05+ 1/2 ton and my fans seem to work fine.

Question is do those with factory installed fans have the fans kick on at cold idle in the winter time with the defrost on? I really think that is dumb to be honest with you. It totally defeats the purpose of me getting rid of the clutch fan that likes to freeze on and pull cold air through the rad at cold idle. I know I can disable the A/C and then it never would cycle them on but is this how every factory e-fan truck operates?

My fan settings are just a segment swap from a 2005 5.3 powered 1/2 ton with the settings modified for my HD trucks factory 186 degree T-stat.

 

Yep every time the A/C comp. is activated so is a fan.

 

That's retarded. Oh well, guess I will have to kill the a/c for the winter months like I used to on my old TBI truck years ago.

 

When you're warming up, the thermostat is closed so the coolant isn't being affected any by the fans running. It's just to pull air across the condensor so the a/c system can condition the air, ie dry it out so you don't fog in the winter time.

Guess I don't see the problem here??

 

I do, big time. Clutch fan does the same thing. Your in what, Arlington Texas right..... No offense but you don't see anything remotely cold. In cold weather, like -20 F or lower, the viscous clutch fan always froze enough to sit there and cool the engine bay, just like these silly e-fans will I guess. It's amazing how much heat an engine will lose with a stupid fan creating a wind chill under the trucks hood. Problem is that when the T-stat opens, it will cool the engine down enough close the t-stat again and keep cooling it until the heat in the cab starts to fall. Once your rolling it's non issue, but then load and rpm are a factor....... not idling at 600 rpm. It's annoying and every truck I have ever had does it. So you stick on some fugly winterfront to combat it.... Nah.

My old LT1 Caprice would sit at -30 C weather and idle at full temp...... hell it would get warm enough to cycle the fans occasionally as it would get too hot idling. On the flip side that cars a/c never did work because it leaked so bad...... so no constant fan running with the defrost. No winterfront, no bellypan, nothing.

If it's not really cold I won't worry about it, but first cold spat and the low pressure switch gets disconnected.