dmcc280z

I have a 1983 Turbo with 50K miles and the Auto Climate system. Currently, the AC and heat seem to work. However, when I move the temperature control off the low setting past the first detent position with the AC on, it goes from cold to warm and then eventually alternating luke warm to cool. This is with the setting in the Auto mode. Blower blows low or high depending on the speed setting.

If I move the temperature control back to the lowest setting (below 65), a couple of seconds later, Wham!. A door under the dash seems to slam shut. Is this normal and any idea which door it might be? Air mix, bypass? The diverter moves the air to the correct location (dash, floor, defrost) but this slamming seems to follow the move from lowest setting to anything above that and back to lowest.

Also with the Economy setting, the blower is on full tilt and only runs at this speed until moved to a setting above 65. Is this normal as well?

The AC compressor seems to have a whine that goes up and down with engine speed. Could the system have too much Freon? Currently it runs R-12 with 2.2lbs. in the system (upper service manual limit). Should I have it evacuated and recharged with 2.0lbs to see if the whine will disappear? Have read that an overcharged system may develop a whine.

Any help? I only have experience with the S30 AC and manual S130 systems. The service manual for the '83 is a doozy when it comes to troubleshooting this one!