usally it is because of a cracked vaccume line(hose) from the intake manifold to the dash controls.usally heat makes the line crack-some vaccume canisters develope a crack in them - this will cause the same problem probably the vacum value connected to the vent controls. If there is a broken vacumn line or if the value is bad, it could cause this to happen
if you are talking about the automatic sensor that automatically turns the lights on and off, it is on the dashboard probably in between the defroster vents it is probably a small plastic or glass bubble usually you have to remove a large portion of the dashboard to replace it
You are having a vacuum loss. Check the hard plastic line that is on the right side under the hood for holes. I replaced mine and it fixed the problem. 1992 F150
The Ford F1 50 air conditioning vents are held in place by four retaining clips. Pry outward on each retaining clip. All of the air conditioning vents can be removed this way.
approximately 4013 lbs.
One reason a 1989 F-150 may not start is a bad battery.
front passenger site
to the rite and just below the coil
www.motorcraft.com shows (.044 inch ) plug gap on the 1989 F150 300 cubic inch ( 4.9 L ) straight 6 cylinder engine
this is my truck and i have exhausted my options i have also replaced the thermostat. It's not just the dash vents it's also the defroster and floor. The heater cor works fine and the cold/hot cable is still connected on each end and the vent flap works to. please give me some suggestions. E-mail me at email@example.com thanks
If antifreeze is filtering through your ac vents, other toxins could also be coming through. Don't take chances; see a mechanic.