This 2002 Cadillac Escalade has an HVAC problem. When A/C is selected on the control unit, cold air blows in the back and warm air blows in the front. This is caused by the blend door actuator not working properly. You can fix this problem by replacing the blend door actuator. When you install the actuator, you must reset the computers that control it.
THIS IS HOW YOU RESET THE BLEND DOOR ACTUATOR:
Step 1: Disconnect the battery (negative terminal only), let it sit disconnected for 1 minute, then reconnect.
Step 2: Turn the key into the on position so the dash lights up, let it sit for 3-5 minutes, then turn off the key, and let sit for 30 seconds.
Step 3: enjoy your new blend door actuator
You can order the blend door actuators on Amazon http://amzn.to/1RGDZx7 make sure it fits your year and model and it is the right one before you order!