I suddenly have cold air coming through defrost vents only, not through dash vents. Defective parts are buried behind firewall on engine side, not accessible without much complicated disassembly. A number of You Tube how-to videos show an easy "bypass" replacement of vacuum hose, check valve, etc., fix to restore normal AC vent control. Ignoring the problem allows loss of vacuum and affects proper engine operation.I'm hoping that a local RV repair shop can do the easy bypass repair at a reasonably small cost.

How do you know the defective parts are under the dash? Did you confirm you have have vacuum before the firewall?

I agree with carrying. Usually all of the actuator are inside the cabin.

You don’t need an rv shop $$. Any mechanic that has van experience will work. You just need someone willing to work outside if your rig doesn't fit in the bay.

Older E-Series used vacuum actuators while the newer models used electric.

Pretty sure from all the videos that my 2004 Tioga E-450 has vacuum actuator. There is a small length of rubber hose that rots and breaks and a check valve that is buried behind the engine, behind firewall. At 83 I can't do DIY much crawling under dash, etc. This sounds like a common problem on older E-450's.Ford should have made maintenance easier.

E-450 Stuck on Defrost Mode | Good Sam Community

Bordercollie
Explorer
Feb 05, 2022
Pretty sure from all the videos that my 2004 Tioga E-450 has vacuum actuator. There is a small length of rubber hose that rots and breaks and a check valve that is buried behind the engine, behind firewall. At 83 I can't do DIY much crawling under dash, etc. This sounds like a common problem on older E-450's.
Ford should have made maintenance easier.
theoldwizard1
Explorer II
Feb 05, 2022
Older E-Series used vacuum actuators while the newer models used electric.
bobndot
Explorer II
Feb 05, 2022
You don’t need an rv shop $$.
Any mechanic that has van experience will work. You just need someone willing to work outside if your rig doesn't fit in the bay.
theoldwizard1
Explorer II
Feb 05, 2022
I agree with carrying. Usually all of the actuator are inside the cabin.
carringb
Explorer
Feb 05, 2022
How do you know the defective parts are under the dash? Did you confirm you have have vacuum before the firewall?

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E-450 Stuck on Defrost Mode

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