I currently have an 03 E-350 7.3L Dually Ambulance. We just had the Vacuum Pump replaced by Ford, and the blower motor replaced by me. Somewhere in between these 2 repairs, the AC Started to only blow out of the defrost vents. It will not blow on anything else, regardless of where the selector is. I have tried to find a vacuum leak, and i only found 1 or 2 lines. Im hoping i dont have to tear apart this dash. If anyone has any insight, please let me know!

 

Verify

1) The pump is actually pumping.
2) A steady vacuum is being delivered to the front HVAC control head.

 

I was able to get it fixed. Followed the lines through the engine compartment, found a vacuum line that had a hole in it, replaced it and kept going. There was a connector connecting the main line into a secondary line that goes through the firewall. The main had vacuum, but through the firewall somewhere, it lost it. I couldnt access the Secondary without taking the wheel well out and doing some extensive searching, so i bypassed the firewall, bought new hose, and went straight from the main line through the "dogbox" and then connected it to the other side of the firewall. It now works and blows out of the vents. Its amazing how one SMALL leak throws everything off...lol.

 

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