New Member W/ a problem

Hello All. Im Matt and from the BMW world. But my GF has a 1991 seville that has a heater problem.

About 4months air stopped coming out of the vents and only would come out of the defrost vents. And would only work on HI at 90degrees with the defrost on. Now, yesterday I was doing some work on my BMW when I had to run to the dealer for a few parts when the car had no heat at all. The defrst vents were just blowing cool air. any ideas? I flushed the system and replaced the t-stat, to no avail.

The car has less than 110k, new waterpump and radiator about 10k ago.

I i need to fix:
-get hot air
-get it to come out of all the vents
-get it to work on all settings not just hi,


any help would be great, Thanks

Air out wrong outlets - Door actuators are vacuum operated. Check for vacuum leak in engine compartment. Check vacuum at reservior first.

Cold air - Check air mix door motor operation. Remove glove box to see it. Motor is part of programmer.

Checking for codes may be helpfull also.