HVAC do not blow sanelly

Hi, Grand am 2002 se1 2.2L ecotec L61

What could cause the HVAC to not blow up correctly?
The dash have 5 air traps, one near each window and 3 at the center.
The sides one blow I'ld say 3/4 of it's normal power.
Centers one, left/right maybe 10%, center maybe 1/2.

I did not checked the floor one, windshield one seems ok, but can't say much because I rarelly use it.

Blower seems fine, as the noise is the same as it always been, so no slow down, and as noisy as always.

It started all of a suddent... Is that a vaccum leak somewhere? or something broke in the selector thing? Or something else?

Sounds like something is up with the mode door. Either binding, actuator problem, vacuum issue (like you said). The mode door actuator is a real bear to replace on these, lets hope it's just a vacuum leak at the switch. Apply vacuum to the mode door actuator and check operation. Just in case, are all the vents fully opened?

sadly, yes, they are all opened. closing some do not improve significantly the flow of the others.

How do you do the test?

You need to find the vacuum hose to the mode door actuator, I'll try and post an illustration. Then apply vacuum to the actuator and see if it moves full travel. If you can reach it, try and move the door by hand stop to stop.

Could'nt find a illustration, but it looks like the mode door has one red and one yellow vacuum hose to it, so you may have to plug one off to get it to operate with a vacuum pump.

If all your vent registers are completely open, and you have your selector on vent, and blower on high.....now if one register is blowing hard and the rest are not, it's not a vac problem......it's some type of blockage......

Could be a mouse house?

hmmm I wonder how I'll be able to check that...

I'll check something this week... with luck I'll find out how to remove the grill and see if I can somehow fit a camera or something...