Originally Posted by jtintx
I took the faceplate off of the thermostat and see that the wires are soldered in place. I've never done any electrical work so don't know how I would go about disconnecting the wires. Do you just cut them? Don't know how much extra wire is in the wall.
First things first.
Unplug your TT.
Disconnect the battery. Its a low voltage circuit but still a charged circuit.
Take the thermostat cover off.
As mentioned before take a pic of the wiring connections.
Have 2 bigger sized (thick) zip ties handy.
Take the thermostat loose from the wall, probably 2 small screws.
Pull the thermostat; with wires still attached, away from the wall to determine how much slack in the wire is available. Don't pull to hard as to pull it loose from other connection but your gonna need some slack.
Once you have the wire pulled from the wall, take the zip ties and put them at the base of the wire at the hole. With one tail of the tie going to either side of the hole. Making real sure the zip ties are TIGHT on the wire. This will allow the you to let the thermostat to hang free without worry of them falling into the wall once they have been cut loose of the thermostat.
Note. You don't have to use zip ties, you can use tape or a bread bag tie. But with those items its hard to get them tight around a wire and you don't want the wires to get loose.
Get your wire cutters out a cut the old thermostat loose. Be sure and cut as close to the solder as possible without cutting the solder ball. This will insure the wires won't fray much. Then get the wire strippers out and strip a 1/4 inch of insulation off the wire.
Finally, get the new thermostat out. Read the connection instructions. Compare the instructions to the pic that you took of the original wiring connections. There will be connection screws, so no soldering will be needed. Make your connections. Matching your pic.
Reconnect your battery and plug in your TT. Now you can test your new thermostat. Make sure you test the A/C AND HEAT controls.
Hope that helps,