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1998 E250 air comes out vents only in defrost mode
Defrost/vent door in the dash isn't opening and closing, but the vacuum pump is moving. All actuators are functioning. Vacuum is good. After several days of searching, this is what I found. Is it possible the internal door in the duct is stuck and broken? What is the access to it. There's nothing on this in any thread or you tube video that i can find. Thanks Under that foam you can touch the door in the duct
Please look at the ENGINE section there are 6 possibilities so which one is yours? Have a look at my signature just so you know why in order to get you the correct diagram and avoid blind guessing of your engine size on my end.
So can you hear any clicking noise at all?
If,,,,,,,,,,,,,that is material from little 4 legged visitors,that needs to be cleaned out so you can see if there was any wiring or vacuum line damage.
It could also cause limited motion of parts that need to move.
Please look at the ENGINE section there are 6 possibilities so which one is yours? Have a look at my signature just so you know why in order to get you the correct diagram and avoid blind guessing of your engine size on my end.
So can you hear any clicking noise at all?
my engine is 5.4 Vin L
Last edited by Completeasshole74; Apr 17, 2024 at 07:00 PM.
Please look at the ENGINE section there are 6 possibilities so which one is yours? Have a look at my signature just so you know why in order to get you the correct diagram and avoid blind guessing of your engine size on my end.
So can you hear any clicking noise at all?
If,,,,,,,,,,,,,that is material from little 4 legged visitors,that needs to be cleaned out so you can seen if there was any wiring or vacuum line damage.
It could also cause limited motion of parts that need to move.
The material is paper insulation and the vacuum lines are all good. All have vacuum. All three vacuum motors are moving
You said everything works fine in defrost mode so let's compare them:
Full vacuum or no vacuum in every selected mode:
You said vacuum lines are all good. All have vacuum.
You have vacuum doesn't mean you don't have a leak. Go over Pinpoint_A.pdf below for the proper way to test that.
If you think the switch is bad, check Function_Selector_Switch_Testing_Procedure.pdf (pretty easy continuity test) and Function_Selector_Switch_Removal.pdf
You said everything works fine in defrost mode so let's compare them:
Full vacuum or no vacuum in every selected mode:
You said vacuum lines are all good. All have vacuum.
You have vacuum doesn't mean you don't have a leak. Go over Pinpoint_A.pdf below for the proper way to test that.
If you think the switch is bad, check Function_Selector_Switch_Testing_Procedure.pdf (pretty easy continuity test) and Function_Selector_Switch_Removal.pdf
I replaced the check valve and selector switch. All good with vacuum. All control arms move to close and open positions. The vacuum reservoir has always been eliminated, due to being broken internally. It never bothered me too much when the air cut out in hard acceleration. But, I plan to add it back in, just been lazy about it. After going through the multiple test charts, the last one refers to repairing or replacing the damper door. That was coincidentally my first assumption after two days of messing with the testing and process of elimination. As I stated in my original post, I was able to push open the damper door through the foam duct seals in the Pic provided. My assumption is it won't go back, because it is detached below, where I can't see, or off track. Not sure about it's mechanics. Thanks for all the charts and info.
1998 E250 air comes out vents only in defrost mode
