I'm thinking they charged $70.00 or so for the diagnostic scan, $15.00 for the thermostat and seal, and maybe $20-30 to install it. It figures out OK, I guess. Unfortunately, that's how the repair business works. Sometimes the "checking it out" part is more expensive than the repair itself. But, I would think they would've called you first telling you what was wrong, knowing that you put the thermostat in in the first place.