05 e450 ambo AC/heat vacuum help

[bgflyguy]

I can't get my AC/heat to blow out of my main vents, only the floor. I took the panel off of the top dash and if I manually push the vacuum switch? It blows out of the vents.

I watched a bunch of videos of bypassing the reservoir under the hood, but I tracked my vacuum line to a plug. It looks like someone has already done something?

How do I troubleshoot this stuff? Any ideas about what could have been done?

I know it seems silly but I don't know how any of this vacuum stuff works. How much pressure should I feel on a functioning line? How can I test the switches(what are they called?)

 

[NatersXJ6]

Start by getting a vacuum gauge and a small hand pump like a mity-vac or similar. You can spend a lot of money guessing and throwing parts that are better spent diagnosing. Most people would call the items you are referring to switches, or valves. If they are electrically activated they would be “solenoids” in most common language.

Is your rig gas or diesel? It makes a difference in vacuum systems.

you shouldn’t feel any pressure on any hoses. Vacuum is vacuum, suction not pressure.

Im not familiar with those Ford Specific systems, but generically, a source (reservoir) provides vacuum to switches that divert it to actuators that actually move the doors on the heater core and ducts to redirect the airflow. Common failures are due to leaks, commonly at the switches, bends or kinks in hoses, or actuator seals.

Sometimes you can hear the leaks by using about 4’ of tube as a stethoscope, put one end in/at your ear and move the other end over likely leak points. You can hear the whistle (Engine running).

 

[FordGuy1]

Its the vacuum reservoir behind the dash. It sucks to replace, but you can remote mount one a leave the factory one where it is and just not use it.

 

[killacks]

Its the vacuum reservoir behind the dash. It sucks to replace, but you can remote mount one a leave the factory one where it is and just not use it.

Link to Vacuum Reservoir repair kit...

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