I am having problems with wiring up a thermostat. We have a Trailer with an electric furance and an outside A/C unit. There are a red and white wire from outside.and a 5 wire from furance to thermostat. The furnace has RC RH G C W. I need help.

Usually there is a 24 volt AC transformer in the furnace with the secondary winding connected to a red wire running to the thermostat and a blue wire, common, to the gas valve, A/C relay, and fan relay. From the thermostat there will be white wire to the gas valve, yellow to the A/C, and green to the fan. The thermostat is wired to switch the power from the red to the white, yellow, and green as needed with the blue completing the circuit. Most thermostats and furnaces have the contacts labeled R, B or C, W, Y, and G for the corresponding wire colors. It may be wired to have the A/C control wires return to the furnace and its controls and then a second wire goes to the A/C unit. Internal wiring may replace the green wire if the thermostat does not give you the option of fan only or continuous fan.

Your furnace does not have the typical Y terminal. Check the thermostat. If it has a Y terminal, the wire from it must connect to one of the wires going outside and the other to the C terminal. RC or RH at the furnace should connect to the opposite terminal on the transformer as the C terminal. You must identify that connection and connect the red wire to the thermostat to it. If once you check the thermostat, you don't have enough information to wire it up, post back.