The answer to your problems is ta-da!! the a/c controller contacts are worn.
The a/c controller in your Malibu has graphite contacts which become glazed over time from energy flow and knob adjustment.
When this condition develops, two anomalies occur.
One, the blower motor receiving a weakened signal, generates lower motor speeds and consequently reduced airflow.
Two, the signalling to the a/c clutch can become intermittent and the a/c will revert to vent only and back.
To repair this problem you can do one of two things. Either spend $175.00 for a new a/c controller, or remove the controller and repair it.
The repair is relatively simple and takes less than an hour. The a/c controller housing is a snap together design that with a little care can be opened without breaking. First, remove its knobs to facilitate its opening
Once open, you will see two sets of grapite trace on the PCB board. The glaze on these traces from the metal glides should be evident. You need to remove the glaze and restore the graphite surface.
To remove the glaze use a pencil eraser. Follow the trace in a lengthwise sweeping motion. Do this for each of the four traces. If the glaze is still deep, use a hobby sanding stick with a fine sandpaper, sanding in a lengthwise motion. Next, put rubbing alcohol on a cotton swab and clean the contacts of debris and of the acid left from the pencil eraser.
Now that the contacts are glaze free (or pretty close) take a #2 pencil and draw over the traces lengthwise. Cover the traces with a thin layer of pencil graphite. You can lightly swab the traces if you see any new debris.
Place the controller buttons back into their positions (They probably fell out) and reconnect the two halves of the controller body. Re-install and enjoy cool a/c again.