I have a 2 stage heat pump system. I've recently purchase a new thermostat. While doing this install, I noticed that I had ome unsed wires tucked away. Not sure what the go to, as they are purple, black, light brown and blue. To see if they were connected anywhere, I went into the garage and took off the panel and noticed those wires were cut and unused. Why are these wires unused and what would they typically be used for?

Many times installers add more wires than needed as you can purchase stat wires with different # of wires in sheathing.The extra wires could be use if you add othe components to the unit in the future. It is great to have the extra wires if one now used gets a break in it. Makes it a lot eaiser to just change the wire rather than having to pull new one through the wall. I always install a bundle with more wires than needed just for that reason. Hope this answers your question