Constant air flow from HVAC system - even when OFF

[bkboatnsleds]

Details..

2003 Tahoe Ls Manual Dual control HVAC system..

No mater what I do I can not stop the airflow from the vents. I put it on dash or floor, and push the Recirc button .. still strong flow.

At highway speeds its almost the same amount as if I had the blower speed on 1.

Only think I can think is I have a door thats not closing.. Thoughts?

 

[FERGHOE]

They all do it. Not sure why other than forced flow while at speed.

 

[yukonjacks]

Last week, I wanted just fresh air and I had hot air coming out, so I put the A/C on and I still had really hot air coming out the vents, I tried the floor, defrost, combos and straight on, still all hot air. Parked the truck and went hunting, started the truck up and the air was coming out cold again WTF

 

[BlizzardX23]

I've noticed while I have the air turned off, its still blowing down below through the footwell vets...and yea, it shouldnt be that strong...I have always wondered what that was about

 

[JKmotorsports]

The low air pressure area at the base of the windshield while driving forces air through the hvac intake. The faster the vehicle is moving, the lower the air pressure in the cowl area, therefore causing the higher air pressure to force more air into the lower pressure area. Aerodynamics. This is the same concept behind cowl induction.
If you have the system in recirc mode, the flow from outside of the vehicle should be blocked off. If you're still getting flow, it's possible you have a duct flap stuck open, inoperable actuator, bad module, or blower motor that isn't turning completely off.

 

[Cobra]

I like it keeps me from using th ac all the time esp. on the highway. I just change temp to hot or cold depending to where I want it and I get it without using system. The only way I can get it to stop is like JK said using recirculation mode.

 

[bkboatnsleds]

I like it keeps me from using th ac all the time esp. on the highway. I just change temp to hot or cold depending to where I want it and I get it without using system. The only way I can get it to stop is like JK said using recirculation mode.

Exactly!! But when I push my Recirc button it does not stop. I know the blower is turning off - I have a stuck vent or a bad actuator motor. Anyone know where it is?

 

[JKmotorsports]

You can try letting the actuators re-calibrate and see if that helps.

Remove the HVAC/ECAS fuse for at least 10 seconds then re-install.
Start the vehicle and wait at least 40 seconds. The HVAC modules should recailbrate and sync.

If this doesn't help, it may be a mechanical problem like a sticking flap or just a bad actuator.

 

[bkboatnsleds]

You can try letting the actuators re-calibrate and see if that helps.

Remove the HVAC/ECAS fuse for at least 10 seconds then re-install.
Start the vehicle and wait at least 40 seconds. The HVAC modules should recailbrate and sync.

If this doesn't help, it may be a mechanical problem like a sticking flap or just a bad actuator.

I tried the re-cal trick .. no luck. Any idea where the flap or actuator is located??

 

[fatnlowtahoe504]

Last week, I wanted just fresh air and I had hot air coming out, so I put the A/C on and I still had really hot air coming out the vents, I tried the floor, defrost, combos and straight on, still all hot air. Parked the truck and went hunting, started the truck up and the air was coming out cold again WTF

mine does the same thing, it seems like when it gets hot sometimes during winter days the a/c doesnt work