dashboard A/C on the fritz

I thought I noticed something similar on a previous trip, almost like the fan stopped working for a while then started up again. Last trip didn't notice anything, but wasn't that hot so I didn't use it that much. A number of years ago had the AC quit working on one of my cars, several days across country with no air. Turns out it was a bad AC switch. AC charge can be checked with an ac gauge attached to a freon can at the auto parts store. Check the electric clutch on the compressor, you can hear/see it engage. Is the drive belt in good shape? Most places that do AC charging will do ford e-series motorhomes.