I am having an intermittent problem with the air conditioning on my
96' Lesabre. When the A/C is on (max, normal or bi-level),
occasionally the vents will switch to defrost mode and get stuck
there. Usually switching from heater to a/c max a few times resolves
the problem (temporarily), but sometimes I have to shut the engine off
to get the proper airflow again. It does not happen all the time, but
usually every 3rd day or so.
I notice it usually happens when coasting, a few seconds after I
remove my foot from the gas. This migh just be cooincedence, but I
thought I would mention it.
I recently had to replace a bit of rubber hose for the evap emissions
solenoid, it had rotted and cracked. I am thinking the same problem
might exist for the vacuum feed to the vent control, but cant seem to
find where it connects to the engine.