2000 4Runner AC/Heat control

[tahoe22]

Under the passenger side dash, there's a motor that moves an arm to adjust the temp up or downward. Well, something with mine broke & I don't have the $ to replace it right now-so I have to manually change it by moving the VERY STIFF arm to the left or right.

This is so tight, I'm scared of breaking the arm off the actual control. Does anyone know which direction this arm needs to move in order to go from AC to heat?

Thanks!