how do i check my temp control actuator on a 2003 dodge ram 1500?

[Mike]

i was told that this is my problem because all heat and AC works fine only problem is when turned to heat and dash vents it blows cold air on drivers side and warm air on passenger side please help give good details because i'm not the worlds best at this kinda stuff and if the could be a way without have to take the whole dash off that would be nice thanks so much