There is a door that diverts the air from the floor to the roof vents. It is controlled with a plastic gear and arm. The gear has stripped out and needs replaced. It's a $35 part but it takes a few hours of labor to replace it because you have to remove so much of the interior to get to it.
how to reset the airsuspension on the 2004 Lincoln navigator
Not using premium fuel caused that in my 2004 Navigator.
It could be one of your vaccum lines that collapsed
The Ignition Coil is the one that cause misfire or Spark Plugs
A Lincoln Navigator will become stuck in 4 wheel drive mode if the actuator is damaged or the fuse is blown. Connecting an OBD II code reader or taking it to the dealership can narrow down the cause.
Turn signal flasher module?
If you have power seats in the Lincoln Navigator, and they won't move forward or backward, it could be that the switch is worn out and needs to be replaced. Also, there is a chance that a switch wire came off or is loose.
brake switch located on the top of the brake pedal
on my 2000 town car it was the idle air control valve sounds like you have the same problem
Auto Zone will check your engine codes for FREE. After finding out what cause your engine light to come on. Then the problem can be resolve with out guessing.
It could be spark plugs or coil packs. Auto Zone will check your computer codes for FREE. This way you won't be guessing.
Broken/ disconnected return spring? Worn brake pad? Loose caliper?