I replaced my thermostat due to the fan not running in auto, suspect contact not making inside thermostat. It is a gas pack. I purchase a gas/cooling thermostat, I hooked it like a four wire: r> rc-rh jumpered together, green to fan, y to y and black to w. The unit will not cut off now. The only way to get it to cut off is put it in the off position. Therefore the fan and the compressor do not cut off. Please help:

Sounds like it is wired correctly as one might think but did you make sure the wires were connected this way before, some installers don't stick to the color code, also make sure the wires are not touching in the subbase and pushed tightly into the wall. Mike