Hi All,
i keep on getting air form the A/C ducts although its off!
i sealed the fresh air vent on the right side but still i get that air flow
any ideas?
its very annoying

 

How did you seal the fresh air intake? The entire cowl area (above/behind the firewall) supplies air to the hvac fresh air inlet.

 

i sealed the hatch thats located under the dash board on the passenger side underneath the fender. isn't this the fresh air hatch? or there is another one?

(its an 87 K5)

 

Well, yes and no. The doors that are down low on either side in the foot well are the fresh air intakes, but the HVAC system also pulls from the cowl area under the hood. If the doors aren't properly sealing in the hvac system, it can cause air to blow out of the dash vents as well.

Also, if you sealed off just the passenger side vent, then you still have the driver side vent that could be allowing air in.

 

i couldn't find a driver side vent!! only on the pass side
do u have a pic of the HVAC door that needs to be checked? or a description

 

No I do not and I don't have time right now to find anything...

I know they changed the side doors from manual to more of an integrated control in the time span between my '74 and your '87. I haven't had a reason to look on the driver side of my '90 suburban parts truck to see if they still had the driver side fresh air vent.

 

no problem, thanks for the help
i'll check www.lmctruck.com and try to point out the vents that needs to be checked.
tkx again

 

Well... I took some time.. A little bit of internet searching tells me that the newer K5's only have one vent.

The valve is closed during all normal operation of the HVAC system and is only open when MAX AC is set on the HVAC controls. This allows the blower fan to pull air from inside the cabin instead of cooling outside air. So you need to look elsewhere for your problem.

I suspect that one or more of the doors is not functioning properly. The system will not be totally sealed when off, but the air should be diverted to the selected location whether defrost, floor, or dash. You have a combination of mechanical and vacuum actuated doors in the hvac system. It is possible that the vacuum supply has come unhooked and has resulted in all of the doors resting at their default position.