Need help dometic 15k ac

[KIPKERS]

My folks have a xlr with a dometic 15k unit in the main. The unit will not turn on, thermostat will turn heater on but no power to ac. They just got back from a week trip and it worked fine then. And yes the breaker was checked and is on

[SeaDog]

When you say no power to the AC does that mean there is no 110V available at the unit or it just doesn't start? A breaker can look like it is on and not be allowing power thru, Test the breaker with a meter and see if it is truly allowing power to pass.

[Bama Rambler]

What year is the A/C?

As SeaDog said, be sure the breaker is passing power to the unit.