My ac/heat control will not switch to the vents. I replaced the mode actuator

no, it will switch from defrost to floor but not to vent. The white gear engages in the black gear but only a few teeth.

have you checked for vacuum leaks under the hood near the fire wall?

no, what would a vacum leak have to do with the operation of the mode actuator.

when you have a vacuum leak,the blower motor will DEFAULT to the defrost and floor mode.very common problem on lots of vehicles.may not be your problem,but i have seen it many times.usually it is the smaller lines next to fire wall,or could be one in the engine area?won't hurt to look!start engine,lift hood,listen for hissing sounds.run your hands around vacuum lines,look for split,cracked,dry rotted hoses.vacuum hose is cheap!!if this is the problem,it's an easy fix!

I did not see any problems with the vacuum lines on my truck and did not find any lines going through the fire wall.