I ran the a/c for about 15 minutes because it hasn't been used in a while and right before I shut the car off I turned the ac off but it kept blowing out of the bottom vents. When I went to drive home I just put it on vent and the car was stumbling a little like it has a vacuum leak and it threw code 32 for the EGR. I just replaced the EGR valve, solenoid, and the vacuum lines for the EGR system. The ac works like it should for all the settings; high, normal, bi-level, vent, etc. but when put on the off setting it blows out of the bottom vents only. I disconnected the battery to reset the computer and went for a drive and now it drives normal except at a stop sign the idle drops slightly low. What could be causing this?

do you mean the compressor is still turning, or do you mean that there is just air coming out the heater???

because in the older gm cars, even when the selector is in the off position, the blower runs on slow and air comes out the floor ducts for vehicle ventilation.
just closer to the 2000 year model year, they started making "off" actually off.

The compressor still runs when it is in the off position. It will blow hard when set to high with the dial. I just went out to test it and now nothing works, no ac, no heater, no vent.

Sorry I don't have any input on how to fix it, but damn you for needing AC. Its a terrible 28* here right now.

so now there's no air out any of the vents, wether it's on or off, and the compressor is still running?, and then when it is on, there's only air when it's on high speed??

Now there's no air out any of the vents, wether it's on or off, and the compressor won't turn on. When it was turning on, it would blow on low or high out of the bottom vents only, when it was in the off position, the rest of the functions worked like they were supposed to.

i can testify to this, but it seems the faster i go, the more air flow i get out of those floor vents when its off, i wonder if that is normal

yes

sounds like there's now a blown fuse.
but it also sounds like the control head has an issue.... the compressor should only run when in max, ac, bilevel, or defrost.
were the air comes out is vaccum controled. so if you have an issue WHERE the air comes out, you have to check the vaccum supply and the vaccum switch attached to the control head, and the vaccum servos that actuate the doors.
if you have a compressor or blower speed problem, it is electrical. could be the control head, and/or compressor relay, blower relay and/or control head switch.
if it is blowing fuses, you could have high resistance in the compressor clutch coil. unplug the compressor and see if it stops blowing fuses.
that might narrow your search

Sweet, i was gettin a lil worried for a moment

Ok, I have the dash apart. The vacuum controlled servos that actuate the doors all work. The blower motor does not spin at all. The compressor clutch will not engage. I put a power source to the compressor clutch and it clicks like it would when it engages. I put a power source to the blower motor and it works. When I turn the heater on with the control unit, the heater core heats up. Greggbruce, your help is much appreciated. Oh yeah, where is the blower relay and the compressor relay?

If NOTHING electrical about the AC works, it's not something caused by any relays. Don't worry about them.

There are 2 most likely causes; a blow fuse, or a certain extremely stupid connector.

If the fuse is good, then follow the brown wire as it leads away from the AC control head and back into the dash. This one wire is the one that brings power to the control head. About a foot or so from the control head, you'll find the connector in question. I'm betting you'll find a connector burnt to a pile of ash, like everybody else's. If so, chop both halves of it off the wires, and replace it with a set of the BIG HEAVY insulated slide connectors.

---WHAT HE SAID---

FWIW--
the blower hi speed relay is between the passenger strut tower and your ac accumulator (big silver cylinder) in the engine compt.

the ac relay is under the dash, I can't tell from the descriptions but it's either to the left or right of the steering column.

Sofakingdom, are you talking about the fuse in the fuse panel under the dash on the driver side? If so, that one is good. The connector on the brown power wire is good also.

Ok, I have an update. The control panel is getting power. The switch on the backside of the off/max/norm/bi-level/vent/heat/defrost slider was bad so I replaced that. The blower now works but the ac compressor clutch won't engage. Anyone have any suggestions on what to look for?