Could someone tell me how to remove the circuit board from the climate control unit (CCU) in a 1989 420 SEL? I have the CCU out, opened the bottom plate, by removing 4 tiny screws. I have removed the pin from the temp. control wheel. Lifting up on the back of the board, the front push buttons seem to be retaining the board in the case. Does anyone know how to disconnect the 5 push buttons from the circuit board so that the board can be removed from the case for inspection and re-soldering? Will there be anything else that inhibits the removal of the circuit board, other than the
5 pushbuttons?