Is it normal to have..........

[elyon]

Is it normal to have fresh air flowing throughout the heater/AC box with environmental controls all in the off position and fan off? I just replaced the heater core and got a good look inside. While riding down the road, air is coming in at my feet. It has been this way since I purchased the truck.

 

[KansasTwister]

Is it normal to have fresh air flowing throughout the heater/AC box with environmental controls all in the off position and fan off? I just replaced the heater core and got a good look inside. While riding down the road, air is coming in at my feet. It has been this way since I purchased the truck.

Possibly the seal or actuator for the defrost vent? Should be under the cowl.

 

[elyon]

Is there an air door outside the heater box that I am missing? I don't have a diagram to work from.

 

[AbramJ]

All GM trucks have what they call "Power Flow Through Ventilation" which means outside air is continually coming in to the cab. This is designed into the vehicle and normal.

 

[4xcrazy]

Behind the passenger side kick panel is a vent door that opens to let fresh air in. If it's stuck open, yes, you will get constant air flow.

I have an '89 and when I close the fresh air, I DON'T GET any further air flow coming into the cabin.

Yours may be stuck open of some part of the linkage that opens and closes it may be unhooked or broken.

 

[elyon]

Power flow through ventilation must be what I have then. . Not the best design on those cold mornings......

I do know that the door in the passenger side kick panel is open when MAX A/C is selected for recirculating cabin air.

 

[4xcrazy]

Yeah, forgot about the recirculate deal, but still, vents/doors should be closed, I know I don't get ANY air flow through my vents when everything is turned off. What's the point of having a heater if it's going to constantly be pushing cold air through your cabin, just doesn't make sense.

 

[82355]

The air has to come through the heater core to get to you. Unless you move the temperature selector over to the cold side.

Martin