Furnace and Air Conditioner

[tcrsolutions]

I have a 1995 34' Scenic Cruiser. Just recently, I encountered what I thought was a problem with the Thermostat; but am completely baffled. On our last trip, both the heater AND Front Air Conditioner (controlled by the same thermostat) will not work. The blower motor comes on on the heater, but you never hear the igniter attempt to light. Additionally, the fan will come on for the Air Conditioner, but you never hear the compressor engage. The heater is fairly new. I replaced it in March and it has been working fine since. The fact that both the A/C AND Furnace are not working right makes me think it has to be a wiring issue or an issue with the thermostat. I replaced the thermostat with the one in the bedroom and have the same problem. I have checked the voltage on the Red, White, Green and Yellow wires and they all seem to be correct. Any thoughts?