Hi I have a 1996 Mercedes S500 and am having issues with the heat. The problem started when I moved from California to Minnesota, and needed to use the heat.

At first the passenger side wan't blowing any heat at all, not even in the defrost. I had the "water circulator" replaced for $850 which was supposed to make the heat circulate in all the "zones" and make the heat work. There was also some kind of filter that was really dirty that they replaced.With that replaced there is a tiny bit of warm air coming out of both the driver's side and the passenger side.

The trouble is now that there is STILL no air pressure. When you turn the AC on the vents blow hard, or if you push the defrost button air blows hard near the windshield. As for the other vents the heat just slowly seeps out.

*One thing I am wondering is the + button on the "automatic climate control" is stuck in, and not working so the fan speed is set on the mid speed, however when you switch it to auto, my understanding is that the car regulates the air itself. Not to mention on AC the blower blows really hard. So I don't know if this is the problem?

Once the car warms up, the small amount of heat eventually heats the interior up, but it takes a while. Someone suggested getting a new thermostat?

Any help would be greatly appreciated it's freezing cold here, and I don't want to blow more money and not fix the main problem, heat! The auto place I'm taking it to is the only one in town that deals with foreign cars, and I don't know if they already screwed me over, so I'm pretty hesitant to go back without having a clue.

Thank you in advance!!