How do I take the front window out of a junk yard 1992 cadillac sedan de ville ( no battery) without riping the tint?

Code E52 means the computer memory has been reset, usually because the battery has been disconnected or the computer has lost power.

I would wiggle the connector to the light switch it could just be a bad connection likely the master control for all the lighting

1991 is the year
the 10th digit is the year which is M
the trans clutch plates are worn so when cold it will move the car until the trans fluid is warn then it will slip out of gear
DLC I never heard of

Ok It Possible to download it.. From LimeWire To do So Type
Exemple ..Download Cadillac Sedan de Ville 1986 Steering Diagram utility ..then take the one you need ...Good Luck

OK, I had the same problem with my 1990 Cadillac Deville. Had to go to a junk yard where they gave me the entire bolted on assembly. I got a 3/8" impact wrench and unbolted the belt buckle from the frame, and did the same to the one on the assembly they gave me. After that my buckle worked great. The color even matched the old one.

remove the filter with a special removal tool that can be obtained at Auto Zone

Sounds like the doors on the heater exchange are not working or are partially blocked.

Since replacing anything could cost hundreds of dollors, would you really replace it from a suggestion or would you prefer to get it diagnosed properly. It gets expensive when you just throw parts at a car. This really need to be diagnosed properly ( hands on with the proper equipment).

Check power connection by fuse panels under hood just below the center of windshield

Battery terminals like bad or corroded. Replace, and you should be fine.