Seems like you lost vacuum to the heater-A/C controls
Check all the small vacuum tubing under the front hatch and vacuum canister and under the dash between a/c controls and the duct work and blower
Your RV might use engine vacuum, or it might have a small vacuum pump, really small like 4 inches square or smaller , 12v and under the dash
I can explain it to you.
But I Can Not understand it for you !
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Connected using T-Mobile Home internet and Visible Phone service
1997 F53 Bounder 36s