take out your glove compartment(s)
then using a flash light shine the light over towards the left
You will see & you could touch the actuator & feel it move
you can change the setting on the control panel & watch it do its thing.
There are 2 screws that hold the actuator in place
If you take it out, try removing it while the actuator white lever is in the down position. That makes it easier to put it back in place.
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If you look up at the underside of the dash, you can see another actuator, you could move that actuator to the Blend door position & see if that changes what the original actuator was doing.
the OEM Actuators are self calibrating & heavy duty, they are also priced fairly, maybe $40
The actuators can be disassembled & if it is a white plastic gear that is broken, you can rotate the gear 180 degrees & usually they will function correctly again.
Hope this helps, by the way, there are several youtube videos about the HVAC actuators for 3rd Gen Rams
