I need help trying to wire a new thermostat. The original was changed by previous owners and wired wrong, wich mean that none of the inside wires are labeled. I have gotten the AC to work wired up several drifferent ways but it never blows like it should. The air is cold and the fan kicks on but you have to be really close to the vents to even tell the air is on. I looked at the outside AC unit and where the thermostat wire run there are 5 terminals. R, Y, G, W, C. There is a orange wire running from the W terminal and a red wire running from the C terminal to another place on the AC unit. Is this a 5 wire setup or a 4 or less? I bought a new roll of 18/5 wire since nothing was labeled but am not sure which wires to run from the thermostat to the AC.

Any thoughts?

Do you have a heat pump??

The orange wire is a tip off for a heat pump. Usuallythey control reversing valves. There is a more exacting discussion in the sticky at the top of the heating forum. You need to read the sections on heat pumps and thermostatic wires. Then post back saying the sticky gave you the help you needed, or asking specific questions.