A couple of days ago I noticed that the AC isn't blowing cold, just warm. Checked the engine coolant levels, took it to check the hvac coolant levels, checked everything that's visible and it all seems fine. The guy a the hvac shop said it could be the blend door actuator stuck or toast, so I'm taking his advice and trying to reach it to see if that's the problem. With that said, I need to tear apart half of the cabin, so where do I start?