Blend door question maybe?

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Aug 1, 2018 | 09:04 AM

trike1946

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From: NJ where fun comes to die

Blend door question maybe?

On my 01 F350, I drove it yesterday and in the morning the ac was fine. When I got in it to come back after working all day, the ac was coming out the defroster vents instead of on the dash. Is this a blend door thing or ??? And what can I do to fix it? Thanks for any help.

Aug 1, 2018 | 12:58 PM

kurthb

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From: CT

Possible vacuum canister?

Aug 1, 2018 | 01:41 PM

All4ford5.4

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Aren't the mode actuation vacuum on those? If it's a diesel maybe vacuum pump or gas or diesel vacuum leak? Vacuum hoses to hubs are possibility too. I'd start with checking vacuum line where it goes in cab. If you have strong vacuum there then it's inside the cab. Weak or no vacuum problem is outside cab

Aug 1, 2018 | 02:29 PM

Chuck-B

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From: Woodbury CT

My 04 F250 (5.4 gasser) used to do that as well, I never did anything about it, just lived with it, eventually it would come back out the A/C vents. A couple of times it would go back and forth 5 - 10 times.

Aug 3, 2018 | 07:31 PM

trike1946

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From: NJ where fun comes to die

Thanks for the replies. It seems to be going back and forth by itself. Sometimes out the defroster vents and sometimes out the dash vents. The fan always works and the air is fairly cold but not as much volume coming out the defroster vents.
Where is this actual blend door? I assume that it changes where the air comes out. Can I disconnect it somehow and put it where I want to? I am doing site work repairs, working about 2 hours away, outside in the heat. It would really help getting back without falling asleep, if I was good and cold.

Aug 3, 2018 | 07:50 PM

Mike189677

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The a/c is coming out of the defrost vents due to a vaccum leak. This is the default postirion. Vaccum leaks are very common on these trucks I would start at the lines to the hubs for you have shift on the fly 4x4 and work your way up to the the vaccum canister and solenoidand since you have a diesel you will also have a vaccum pump that you should be able to hear running with the key on in the passenger side fender well area under the hood. If your truck has the by pass valve on the heater core line make sure that gray vac line is attatched to the little nipple front of the valve.

Aug 4, 2018 | 06:41 AM

trike1946

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From: NJ where fun comes to die

Quote:

Originally Posted by Mike189677

That explains a little more of the problem. I don't have shift on the fly, I wish I did, so I don't have to check that. I assume the by pass on the heater is under the hood. I will look for that. What is the little silver colored canister under the glove box on the firewall? It has a rod through the center of it. It looks like either a wire or maybe a vacuum line goes from it to a small little square thing with maybe a line and wire out each side. It is just hanging down under the glove box. And there is something that looks like it should have a hose hooked to it sticking out. But I looked all over and did not see anything else near it. There is a white and a black line of some sort on each side. One line going to that silver canister thing.
I am working most of today, but will start looking again when I get back. I think there is a lot more hot weather coming, and having ac will help a lot.