I have a carrier thermostat with red, green, yellow, white and blue wires. Bought a new honeywell, omly has red, green, yellow and white terminals. What do I do with the blue wire. Right now it is connected to rc with no jumper, but nothing works.
This is an educated guess, even though we don't know how the furnace is wired. In many cases, the blue wire is used for C (common). Tape off or snip off the end of the blue wire and don't use it. Put the red wire on the RC terminal. Jump RC to R or RH if you have heat. Connect the other wires to their corresponding terminals. If blue is common, there's a good chance you blew the fuse on the control board (if your air handler has one) and/or you fried the transformer. That is, if you tried turning on the A/C.
