2002 buick lesabre limited , having trouble with the air flow that has a mind of its own, when i need to change the flow of air it stays stuck on defrost, i assume it is either the temperature control unit for the hvac, or it might be the mode door actuator, any thoughts, also if it is the mode actuator i assume i need to remove most of the dash to gain access to the actuator????????

Do a system relearn and see what you get.
Turn the system on full cold Max AC.
Radio OFF.
Turn ignition OFF.
Pull the HVAC (AC) fuse from interior fuse box. Leave out for 1 minute and replace.
Turn key to run/on position....NOT start.
Do not touch any controls. You'll hear the doors (actuators) being opened and closed. The HVAC module is learning the full open and full close positions. Wait until the system is completely done with the learning process. Less than a minute.
Start and test the system.

thank you, I will try that and let you know

I have located the fuse box that is in the back seat next to the battery and inside the cover I found 3 fuses for hvac #2 is HVAC BLO 30A , #33 is 10A and #37 is HVAC BATT 10A therefore which on should I pull??

You are OK to pull them all.

well I tried the procedure that you have suggested and it only blows from the floor vent, I did notice that there is an actuator by the glove box and on the driver side there are 2 actuators, i was able to see with a mirror and flash light that the actuator on the bottom of the driver side works when i change the temperature and also on the passenger side by the glove box that is also works but the actuator on the side that is up above the lower actuator seems to be stuck it does not move at all, I assume the upper actuator on the driver side is for the mode for directing the air flow to the floor and mid vent and the defrost??????

That upper one is the mode (floor/vents/defrost) actuator. Replace it.

looks like i will have to get the saw all out and rip out the front of the dash to gain access to that upper actuator!!!!!!!

There'* usually a way to cut into the box and get to it and after repair use glue gun and duct tape to repair the box.
Look for a video.

thank you, I assume it might be on you tube????