Ok, here'* a strange one (well, I think so at least...)

Have 88 SSE with the automatic climate control system. With the A/C on full blast (set to 16 celsius, the lowest setting), part of the air comes from the main vents, and part from the floor.

Thought this was kind of sketchy. So, hit the defroster (to see if the HVAC system is still able to move the airflow). Air was directed up at the windshield (away from the main vents), but still down to the floor. Cranked up the heat to 31 celsius (highest) and 100% of the airflow came from the floor vents.

Sooooo..... There is ALWAYS air going to the floor, which sucks when I want the A/C on. Could there be some sort of hole in the system of ducts that is causing this, or is it normal...?

Thanks!

With the AC at lowest setting my just puts out air at the vents. Seems like as the temperature is warmer in the car and colder outside it will share the air between the floor and the vents. Not exactly sure how the system works all together but I know that I like it.

Yes, it should not come out of the floor on every setting. Possibly a vacuum problem or a problem with the doors or programmer. Do you ever have problems with the air switching intermittently between the different vents when you accelerate?

You're lucky that your AC works I haven't fixed mine yet
That sounds like a computer thing. I could be wrong though. The climate control box is easy to replace, and any year will work up to a 1993.

I have the same prob with my 92 sse. When I have the AC on some of the air is diverted below and detracts from the air that should be coming out of my vents. Stuck door? I dunno but I don't feel like ripping my dash apart. Does anyone know how to do some basic troubleshooting on this?

HVAC "programmer" is not really a computer, that is in the control head, rater it is four servo (vaccuum) solenoids with amplifcation circuit (transistor rather than relays) and a seperate servomotor (on the top) to control temperature. There is an intake line (that often gets disconnected on the engine side of the firewall resulting in everything coming out the defroster) and four servo lines to three actuators (one double action) to control the air flow action (DEF, vents, vents & floor, floor) - see chart 6 "Improper Air Delivery" in section 1C of the factory service manual.

Was used in many GM cars from about 1986-1993 with minor differences in electrical connector/placement but the servo solenoids are the same for all.

BTW the programmer only works properly in the "as installed" position, not lying on its side on the floormat.

Would first verify the vaccuum source is good (at least 10") then apply direct to each of the servo lines to verify their operation. If all work then would probably visit the local junque emporium for another.

Have spent several hours on my back fiddling with one before. Would prefer not to repeat.