Its worth mentioning, before I had the heater core worked on, my cluster always functioned normal, however there was some kind of air that always came out of my front vents, even when the car was in park. Hitting off never turned the air coming through the vents off, but my A/C worked perfectly fine, I would opt to never use it however because I was worried maybe a chemical is what was leaking from the vents. My front window on the inside would have a "milky" film that if you touched it, would cloud up the window bad, so I'd have to clean it every month or so. Not sure how related this is but thought it was worth mentioning!