I have an old Honeywell Thermostat model # T651A1269 and there are 5 wires - Blue, Red, Brown, Black, White. The wires are hooked up to numbers not letters. The Red wire was hooked up to a separate on/off button. The new thermostat has letters in the back of it and it is difficult to hook up. Anyone that can help please write a comment. Thanks in advance.

Tell us how the old was wired and the options you have with the new thermostat. Always turn the power off first going to your system to keep from doing damage to the system or getting a electrical shock.

I have a central air system for A/C and Heat (120Volt). I turned off the power from the fuse box, then I looked at the wires and on the old one the red, brown, white and black wires are connected to the cool/heat/off switch separate from the thermostat. Also the black wire is connected to the back of the thermostat to the COMM. Numbered 3. The white wire is also connected to the back of the thermostat to COOL numbered 2. There is a blue and another white wire sticking out of the wall that are not connected anywhere. There is another black wire coming out of the wall connected to the HEAT numbered 1. Also the red and brown wire from the cool/heat/off switch are connected directly in to the wall.

The new thermostat (Honeywell RTH6350D) shows me this https://www.askmehelpdesk.com/attachment.php?attachmentid=37841&stc=1&d=1319986486