CC buttons sticking down
 

Anyone else have this happen? My CC pushbuttons (in 1987 300D) get stuck in the "down" or "on" position. Usually when I push "0," whichever one was depressed pops up. No longer. No I have to finesse them up, and sometimes they still don't go. What's causing this, and is it fixable? (Or replaceable?)

While we're on the topic, here's a question that I stumbled across today. In the owner's manual, which I thought I'd read all of, I realized today that it says the "0" setting is only to be used "temporarily" while driving? :confused: I always thought that was basically the "off" setting and I use it all the time. What setting am I supposed to leave it at if I'm completely comfortable with no heat coming in? The CC works decently at keeping the cabin temp great (not too hot) if it's cold out, but if I leave it on when it's say, 70 out, it would get too hot.

FWIW, the AC compressor is not hooked up, so that's a non-factor whenever I talk about CC.

The clearances between the knobs and the front plastic panel of the climate control unit are very tight. Might be something as simple as dirt or grit getting in there and jamming them. Would require removal and disassembly as the buttons are best removed by pushing out from the rear.
Could also be a problem with the switch assembly release mechanism sticking if it still won't release with the buttons off.
While you have it apart check for bad solder connections (cracks). Usual areas are the switch and temperature potentiometer connections. Also good time to change both bulbs.

I've had some success cleaning the sides of the culprit button with a q-tip and some alcohol and then adding a touch of WD-40. Usually fixes it.

The climate control should remain on economy for nearly all driving conditions. The use of the off pushbutton eliminates all outside air from entering the vehicle. Therefore, it should not be used for an extended period of time.

The economy button should not allow the temp to get too high, if the system is working correctly. However, due to the fickle nature of the beast, it's usually a bit confused between heating and cooling modes when the ambient temperature is about 60F. or so. In such cases, I usually dial the temperature wheel down about three degrees or so. I've definitely noticed that you'll need a temp setting of 22 when you want heat and about 18 when you don't.

Well, this seems to be "solved." I went to take the unit out last night, in the dark ... pulled it out of the dash but couldn't see well enough to get the elec connections off, and didn't want to screw it up (the only lighting I had was my on-again-off-again dome light, the next thing I need to fix), so I just popped it back in to figure out in daylight. Well, the buttons work perfectly now. Maybe just pulling it out and moving it around dislodged some dirt particles or something. Think I'll still take it back out at my convenience and clean up back there. Do the contacts just pop off the back or is there some other trick? I suspect this will be more obvious when I get a look at it in the light.:o