The next picture below shows the ACC unit considerably further disassembled. On the '87 300D, the ACC unit has more electronics in it, and all switch connections are on the bottom circuit board that you can access by removing just the one cover. Here, the ACC unit is mostly mechanical, with larger switches and a second circuit board for another set of connections. It was on this upper circuit board that I found a cracked solder connection.
To get to this state of disassembly, you have to get the cover framing the pushbuttons loose - it is held on by tabs. Then you work down one side, popping off the buttons gently one by one. Once I got all the "MODE" buttons loose, rather than pop loose the fan buttons, I just removed that entire module with the whole pushbutton frame attached. The temperature wheel module on the other side of the ACC unit also pulls off (carefully, there are some tabs holding it).
Finally, the circuit board assembly is leveraged out of the remaining plastic case starting with the back end (away from the pushbuttons).
Last edited by Ken300D; 06-28-2002 at 08:51 PM.