Cadillac Repair: heating problems, fleetwood brougham, letter combinations

Question
i have an 89 fleetwood brougham and when the heat is turned off hot air will sporadically blow out of the vents or onto my feet. what can i do?  

Answer
Most likely you have a fault with the programmer.

Check for FAULT CODES in your computer by:

1. Ignition ON, Engine OFF.

2. Simultaneously push and release the OFF and WARMER buttons when alll the segments display on the display panel.

3. Write down all the numbers and letter combinations that appear on the screen until it stops.

4. Turn ignition OFF.

5. Let me know what the codes are.