Help needed please! 1997 Chevy Tahoe A/C weak airflow out dash vents?

[1rusty72]

Hello,
I have a 1997 chevy tahoe with weak air flow through vents. It's almost like the selection door is stuck in the half position when selecting any of the settings floor, dash vents, defrost....the blower motor sounds strong just acts like it is restricted. Does anyone have any suggestions? I know the control panel works in all positions and it does go through the different positions when selecting just weak air flow coming out. Any help would be much appreciated. Thanks

[speedygonzales]

Is there a lot of air coming out the feet and defrost locations?

[1rusty72]

Originally Posted by speedygonzales

Is there a lot of air coming out the feet and defrost locations?

Yes, air does come out feet and defrost when selected. Air blows the same through all selections.

[Red88]

May be that the evaporator is clogged. Take a look at this from the FAQ.

http://67-72chevytrucks.com/vboard/s...38&postcount=6

[speedygonzales]

The problem is with the selector doors or something having to do with them if you have lets say the front vents in the dash selected and the feet and defrost is also on.

I believe you are getting full air flow just that it's coming out of too many locations at once so it feels weak.

BTW the feet and defrost location is default to many vehicles that loose selector door control. That way your body and the windshield will be ok till the problem is corrected.

I think the first thing you should do is get a visual on the device that moves the doors to see what it is doing. I had the problem with our durango where the loop that rotates and moves the doors had fallen off it's mount cause a screw backed out. Screw tight with loctite and all was good.

If the door mechanism isn't moving, you have to see what moves it. In the case of my old Camaro, it was vacuum powered dash pots. In the case of the durango, it was electric motors. Then see if they are getting the source that powers them. (Either vacuum or dc voltage).

If they are and they aren't moving the problem is simple. If they aren't getting source, then you have to see why. Start with the controls.

[gregory5000]

Could be a vacuum leak. My 2002 Olds Silhouette had that to happen and it was a vacuum leak.

[hatzie]

The control doors run off electric motors. Many GM vehicles have problems with the gears in these motor units.
The 1995-2000 dash control unit is not that good either.
I've replaced both on my GMC.
It's unbelievable how much dirt gets caught by the condensate and stays in the evaporator. A heater/AC box filter would've been real nice. I rinsed mine for quite a long time before the water ran clean out the drain. The airflow didn't appear to increase but the vent temps dropped noticeably.

[ChevyCruizer]

My 99 Suburban had that problem. The air was always weak coming out of the dash vents but when I selected defrost or floor it was much stronger. I bought a new electric door motor, but when I got under the dash to replace it I found that the plastic/spring loaded blend door arm had become disconnected when a part of the plastic broke. A trip to the local pick a part yard had me back in business. For me it was the door that is located near the gas pedal.