REcently I was trying to use the heater in my car and the knob will not move past the middle setting. I try and push it to the heat side, but it will bounce right back to the middle. as of yesterday the top knob controling the air flow (where it is directed) is doing the same thing.... I'm pretty sure I'm going to have to take off the panel but does anyone know how big a project this is or any ideas about how to go about it? Thanks.