OK I feel as if Im getting closer, thanx again guys.

Larry, the dealer said there was no repair kit or insert for the 87 300E, I would just have to pony up the $145.

MBDoc, I took the monovalve off and watched it. When Defrost on the valve pulled in, when A/C, half A/C, economy, or Off pushed in the valve pushed out. This sounds like the pushbutton unit and the monovalve are both good, right? So what next?

I also read that maybe my compressor wasnt coming on, maybe due to low refrigerant. I know there are 2 wires I must cross on the drier to check this. But I have no idea where the compressor or drier are. Im assuming the compressor is one of the pulleys on the belt system, so I can figure that out. But where is the drier so I can see if its low refrigerant?

Help!! I think I am almost there.