Out at Same Time: Central/Rear Roof AC Units

[daveglines]

Hello folks. I have an '82 FC 35-foot Wanderlodge with the CAT-3208 NA engine.
The last time we ran the AC roof units, both the middle unit and the rear unit
stopped turning on at the same time.

Does anyone know if there's a relay that controls both of these AC units? We've
checked the circuit breakers and everything seems fine there. And the controls
above the driver's head are both in the "on" position as well.

Any input is greatly appreciated.

Thanks good people!

dg