Can you hear the compressor come on when a/c is selected. It's going to make a humming noise. If you can't tell trying turning just the fan on low the select the a/c. Should be able to tell the difference if not inside definitely outside on the roof. What's the ambient temp? Our work just fine one and day and not the next. The a/c unit was bad.
Keith and Lisa Ward
2019 Pinnacle 36FBTS
2021 Ford F350 XLT CC LB DRW 6.7L Diesel
Demco 18K Autoslide Hitch
2019 Ford F350 SB 6.7L Diesel (Gone)