Fan continues to blow air thru vents

Kelly · December 17, 2003

The Fan continues to blow air thru the vents while the fan is turned off.

It is hot or cold depending on the temp dial setting.

Is this normal?

Thanks!!

Shaners · December 17, 2003

It's normal while going down the road. It's not normal while sitting still...

Bob G. · December 17, 2003

GM trucks have operated like this since at least my first truck - 78 Chevrolet CK20.

Bob G.

BlackSilver · December 17, 2003

The fan isn't blowing, but air is circulating through the cabin as you move down the road.

MCourson · December 17, 2003

Does anyone know what is the reason for this? When you turn off the air in my 94 it turns the foot fan on.

Wingnut · December 17, 2003

Your feet stink.

chevroletmb · December 18, 2003

the fan runs continuosly to keep a positive pressure in the cab

the reason behind this is to keep exhaust fumes ect from entering the cab.

tmoreau · December 18, 2003

I always knew there was a continuous airflow, thought it was to prevent asphixiation (sp?). Guess that could be true weather its exhaust fumes or just using up all yer air. I know that on jeeps (cj's, wranglers, etc.) there is positive air pressure at the cowl forcing air into the system. Not sure if this condition still exists with modern aerodynamics.