HVAC related temperature switch
 

Here's the deal. I've had problems with my A/C / heat recently, finally gave it up and took it to the local 7 shop. Mix motor and stuff turned out fine (it was permanently on hot) and they think it is a temperature switch which they said is in the back middle of the dash. Long story short, to test it it was going to be 3 hours of labor just to get to it, and the part used would be another $300 on top of that. I have currently opted not to do that, instead just having it switched from hot to cold (it's summer here in the south already). I'm curious if anyone has ever had this part fail or if they know what part # this is. Just looking for some more information on this one before I drop a ton of $$.

Thanks