I have a 2006 Ram 1500SLT Quad Cab.I started to have a problem when I switch my heat from defrost only setting to the floor only outlets the heat still blows out from the defrost.When I switch from defrost to vent the heat blows out the vents like it should.I switch back to floor setting and heat blows out from defrost again.With the truck off and the key in the on position,I go through all the settings one at a time and I hear a motor or something activating with each position.I turn on the blower in the floor position and the air still comes out the defrost.I looked up into the floor vent opening and when I change from defrost to floor setting I see the door starts to open about a quarter inch but then falls back down. Any thoughts? Thank You