The most likely cause would be a vacuum leak at the rear of the engine or a defective selector switch.
the ducts can not be hooked up for the vents to work
Any of the following can cause this......... 1. Bad a/c - heater controller.. 2. Bad a/c - heater controller inside door operation.. 3. Bad, broken or cracked vacuum line/lines..
Check at the back of the intake manifold for any broken vacuum hoses.
There are heater doors on the heat blower box that direct the path of the heat. Apparently the heater door to the floor vents is stuck closed.
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When there is a problem with the vent system it dfaults to the defrost setting. Sounds like you have a problem in the doors that direct the air flow.
I believe the upper vents are for A/C only. The floor vents are for the Hot air. Test your ceiling controls by moving the knob from cold to hot, you should hear the air pass from upper vents to lower vents. Providing of course you have selected REAR from the front control panel.
IF a Vaccume hose comes off OR is bad going 2 the DASH Controls that will happen OR a bad Actuator or Actuator door (stuck) will cause that.Make sure the vaccume Canister is not cracked (if it hs one) Usally it's a very small Vaccume line(hose) that causes the Problem. You either have a vacuum leak in the heater control system, or a cable that has come off of its control panel...
in the floor.
Most temp blend doors have an electric actuator. The defroster, dash vents and floor vents are usually run by vacuum.
Yes vents can be in the floor instead of the wall.
on the floor on the floor