You mention the temperature control unit, does this go by any other name as I cant find that part? The heated seats in my car failed, was told the module needed to be replaced, $400 for parts and labor, ugh,
I did this swap on my wife's 2013 Sonic LT. It is plug and play.
I nabbed a set of used seats from an LTZ Sonic that were in good condition for ~$200. Make sure you check underneath and make sure the electrical connectors aren't corroded or the seat frame showing signs of rust. I came across a set of RS seats that were trash and looked like they came from a flood car. Seating surface looked fine on the RS seats so you gotta watch out. The heated seat control unit is mounted underneath the driver side seat. The unit is not sealed like an ECU is.
I found seats on car-part.com at a salvage yard fairly close by.
For the AC/Heat Climate control, I used this part: Heater Control - GM (95104393) that I'd found used on ebay for ~$30. There were a few different part numbers for my model year, some that super-ceded others. The silver surround was scratched up a little but an extra couple minutes with a screwdriver I was able to swap in my original face with the new controls. There was a video on youtube that showed how to remove the trim. I recommend going to a parts store, amazon, or harbor freight and picking up some cheap trim removal tools so you don't wreck the surface of your interior.
