2013 Ford chassis Class A- dash airflow switch not working

[Bryan F]

This question may be beyond your scope.
My dash control switch the directs air flow to the defrost discharge, vent discharge, AC discharge and floor discharge does not work. The switch worked the day before in the AC position. My investigation seems to indicate that there is no vacuum pressure supplied to the vacuum plug block at the back of the switch control. I believe I have followed the vacuum line to a source that has vacuum. The line goes through the firewall that is sealed with spray foam Insulation and doesn’t move so I don’t know if it is the same line. Can you help trouble shoot this?

Thanks, Bryan

[CIDE]

I had the same problem on a Chevy van chassis, this is what I found - so you're on the right track. Sorry I can't help with the Ford chassis.

This was dangling lower, moved up for photo. It looks to be simply broken -


The backside showed it had quit flowing vacuum long ago - I have no idea how it worked at all.


Quick trip to the hardware store, happy to find metal instead of plastic.


Fixed, total time about 30 minutes. Normally, I'd have replaced the entire line but the limited RV access discouraged that better solution.

[A32Deuce]

That happens a lot with critters getting under the hood.