I have a 1993 Audi 90 CS quattro Sport MT V6 with automatic climate control and broken ventilation.

I am very much a noob with car repair and maintenance, so guidance is appreciated!

When I turn on the air, it seems to blow against something within the dash, and spill out at the feet of the passenger side. It does NOT come out through the official feet vents, but seems to come out downward right behind the glove box. So the air comes on, just not out through any vents, including the window defrost.

I had the heater core replaced, and either the thermostat also got replaced or I had it checked and it was ok (can't remember off the top of my head, it was a little while ago).

The air doesn't seem to get warm, either. But having air come out the vents is obviously more important at this point.

I went through the climate control diagnostic codes and wrote down all 61 of them. The first one is 0.0 though. FYI the fan level does work setting the air to blow softer/harder.

Currently my entire dashboard is removed, and basically my plan is to fiddle around and look for something suspicious, like closed vent flaps.

 

Lots of things can be an issue.
No heat could mean an air bubble in the heater core.
Foam on the flaps can be gone, so air just blows everywhere.
My car has dead flap motors, so the flaps never move to where they're supposed to.
You could have a dead Climatronic head unit not properly controlling the flaps.
It could be a combination of any and all of the above.

 

Thanks for the response.

If there's an issue with the Climatronic unit, would it report a diagnostic error? If so, what should I look for?

Also, if the flap motors are dead, wouldn't the air still be coming out through some of the vents?

FWIW, here are a few of the diagnostic codes (the engine was off, car parked, HI temp setting, window defrost on at ~40%, outside temp ~55F):

Specified value of Central Flap - 0.9
Specified value of Footwell/Defroster Flap - 6.2
Specified value of Air Flow Flap - 0.0

Potentiometer malfunction counters all 0.0

Motor potentiometer feedback value, cold end-stops 23.3-23.7
Motor potentiometer feedback value, hot end-stops 1.0-1.3

Channel 53 Climate system electrical output codes segment a1 ON: Fan for interior temperature sensor

 

Looks like to me its data with no error codes. Was everything working after the heater core replacement?

 

http://www.12v.org/maintenance/index...&ch=ccodes&v=1

 

No, while the cabin did feel warmer, the ventilation itself was not affected by replacing the heater core. And I have no leakage.

The data from the unit does seem valid overall. I guess I don't know exactly what of all of the values mean, though. And I don't know if it is setting the values correctly. If the unit needs to be resoldered, as I've seen suggested before, wouldn't I not be able to get the data? Or is it possible that only changing flaps/routing the air could be broken with bad connections?

Yep, I did use that for translating the channel values, which FYI can also be found here with more contextual info:
http://91.122.15.93/auto/Audi/www.au...mate/90_93.pdf

The central flap does still have foam intact on it, and the flap was fully closed when I pulled off the dash. I can move the linkage back and forth slightly to close and open the flap to about 20% open. The flap that goes to the feet seems to be closed off and I can't find how to move the linkage to make sure that's ok.

I've also taken off the blower, undone some clips, and looked in the plastic housing...evaporator housing, right? The fresh air intake directly behind the blower has a flap that was closed, but it looks like a filter so I'm assuming that's ok.

And inside the radiator on the driver's side there was quite a bit debris with leaves and stuff that I cleared out of the way.

I have no idea how to remove the entire central air unit and evaporator unit, they feel pretty solidly connected. Do I need to undo some bolts in the engine bay or something? I guess at this point I'm hestitant to keep removing things since I'm not sure what I can solve by doing so. If some flap motor is broken or something I'm not sure how I'd know that.

And finally there's a yellow-tinted metallic box with connectors that looks kind of like an ECU behind and below the evaporator housing pressed between that and the carpet. Is that thing supposed to be down there?

 

That link.....http://91.122.15.93/auto/Audi/www.au...mate/90_93.pdf is a great link with great info.

I replaced all 3 flap motors on my quattro. You'll have to remove the center console/glove compartmet and work your way back into where the flaps are.
If you take the knee bolster out and also the glove compartment out then you should at least see the actuators.Then you should be able to disconnect and move the temp actuator to see if you actually have heat coming out.
But first I would open the hood and see if both hoses that go to the heater core are hot. If both are hot then you have water at least circulating.
good luck

 

Oh hey, directory indexing is turned on, woot: http://91.122.15.93/auto/Audi/www.au...rical/climate/

Unfortunately my dash has been out for a couple days, so everything has had a chance to cool down.

I did manage to undo the nuts and the tubing to the heater core. I unscrewed the cooling cap and it didn't release any pressure. It's been sitting for a bit, so I'm not sure if that makes a difference. However, pulling the tubing off produced a little splatter, so hopefully it is indeed circulating.

So then all that's left is for me to undo the clips that hold the heater unit to the evaporator unit? I don't have any other wires or anything to undo, right? I know the manual climate control has those cables.

The Heater Core How-to (https://www.audiworld.com/tech/int55.shtml) does mention this, though:
Both pipes as in heater core pipes? That's the pill-shaped rubber with the separating piece?

Finally, I noticed a small, clear plastic hose just dangling right behind the heater unit. I'm assuming that's supposed to be connected to something.

And I studied what I presume to be the ECU a little more. It must have a screw/bolt that is supposed to hold it up, so I'm guessing it's just not being held up like it's supposed to.