My husband just got a 95 Dakota and the blower will only blow through vents. It works from low to high and cold to hot. You can hear the doors move when you switch to floor or defrost, but the air still only comes through the vents. We disconnected the electrical to help diagnose, and the tester light on the wires lit up on three of the wires when disconnected, but not when connected. Does anyone have any thoughts or advice? Has anyone ever heard of this problem?

 

Sounds like you have a vacuum leak and or bad hoses ect. Start with the vacuum line going to the firewall.

 

The is also a Vaccum line located on the passenger side of the close to the door. This may be why your seeing the door moved remove the passenger side kick panel by the floor board and you will see 2 lines and the vacum canister with hoses. Been there done that. hope this helps also check the control module in the center of the dash it has vacum lines for each position on the heat to cool control. Been there done that. they are color coded hope this helps.

 

Thanks for the help. We will try this.