Coleman mach in 99 Fleetwood

I have 2 ac's. Both were working good last year. This year I tried to start them up and one came on, the other does nothing. I recently had the inverter/charger replaced as well as all jacks. I don't need more repair bills. Any suggestions on what I can do to get it going again? Neither fan nor condenser come on. I pulled cover off the inside and checked all the wire connections with thermostat on and got no indicator, but I really did not know what I was doing.