Vent blend door actuator

In the case of your LS you have a few different units.
The air inlet duct actuator, the cold air bypass actuator, the defrost actuator, the floor duct door actuator and the panel, floor, console duct actuator.

The air inlet duct unit is on the right side under the dash, you just remove the insulator panel and the duct itself, the actuator is just above it on the HVAC case.

The cold air bypass actuator and floor duct actuator are both above the drivers side footwell. You remove the insulator panel and the left air duct and they are located on the end of the HVAC case, The cold air bypass is the upper one.

The defrost actuator and the panel, floor, console actuator are both located on the top rear side of the HVAC case and you need to remove the instrument panel to get to them.