You're welcome.

It has a few light bulbs, see sockets in pic.

How does one remove the switch? Is it still available?

watch this video. relevant section starts at about 2:50
Mercedes Benz 123 Chassis Center Console Wood and Switch Removal by Kent Bergsma - YouTube

you'll know if the automatic control is working by pressing the small button so that the high and low fan selection are both popped out. the automatic control should vary the fan speed. it will never shut off. it will also vary how much heat comes out of the vent. in using mine, it feels like the farther away the target temperature the hotter the air coming out of the vent. the system is very slow to react, by the way. i dont know if thats how its designed or because its 30 years old.

Thank you so much! :D

I will watch it, but interesting you say the automatic pops, as mine doesn't, thus why I was wondering how one knew what mode they are in. Now what?

I found it interesting how far the automatic button sticks out in the video. Mine is missing most of the lettering. What is the unit called? I am thinking of finding a different unit...

It's an Automatic Climate Control unit.

Yep, thank you, I realized that late last night doing research. I thought the switch was separate but in fact part of the whole unit. So that ends getting new and maybe used. In the end, it does work better than nothing! ;) :D

The way you phrased that, I'm not sure if you understood what the other respondent meant by "pops". When you press the automatic button, if either of the manual fan control buttons (above and below it) is pushed in, the manual button should pop out when the auto button is pushed. The auto button doesn't stay pushed in like the others when it has been pushed, it's a momentary switch. Neither does it pop out when one of the manual buttons is pressed to take the system out of auto mode for fan control.

If you do need to replace the unit, auto climate control units new were nearly $400 last time I checked. I would suggest you put a 'WTB' (want to buy) posting on the Mercedes Used Parts for Sale subforum (accessible off the main forums page). Lots of folks have parted out w123s over the last few months so someone probably has one lying around for a more reasonable price. I would recommend that you get a unit out of a w123 -- the early w126 series unit looks identical, and some people say they have interchanged them, but technically it isn't the same. (The w123 part has 123 in the part number.)

BTW, sorry if I came across like a hard*ss in my reply yesterday to you about including model info in posts... likewise apologies to querty for snapping at him. Three days of meds for lower back immobility tends to make me snappy (and causes me to make typos, as querty was pointing out).

Zacharias, thank you so much! :D

I got it now. I thought it was a momentary, but others said it "popped" like the others.

In my research, I found new units are no longer available, only rebuilt. Price range from about $700 for a Mercedes rebuilt unit to about $165 for ProgRama unit (which appears to have the longest warrenty at three years and unlimited miles). Core is around $25 so shouldn't be hard to get a used unit for about that (I wouldn't pay more than $50). For now the plan is understanding, which has been accomplished, then applying Bounty sheet to the inside of the glass to keep down the fog eliminating the need for high heat. ;)

Some folks have success in reflowing any failed solder leads, referred to as a cold solder.

Adriel, you should have either brought your owner's manual with you or Emailed me about this.

The way we always did it was "defrost" until the windows were clear and we were roasting, then adjust the temp wheel to a comfortable setting and press the button with the solid white up and down arrows. This allows the air to come out and windshield and feet, and will keep the W/S clear without roasting you out of the car. If you're running in high moisture, rain, snow, etc. use the high fan setting, otherwise use Automatic.

And yes, the A/C system is activated in all except the "EC" (Economy) mode since the A/C system is also a dehumidifier.

X2

Tram, danke for the help! :D

For the record, I didn't do it your way, but think it would work better: high fan for moist weather. What I do was turn the defrost on until clear, then turn the floor vents on until reduced speed and needed to turn the defrost on. I don't like warm air in my face but love hot feet/legs. If the defrost is bothering me, I open the sunroof and not only cools my face but actually helps clear the windshield especially if only cracked open. I find with just the floor heat still comes out the outermost vents. I discovered these are for clearing the side windows which is even more critical than the windshield as Ember likes to rest her head on my shoulder and fog the window! :rolleyes: l.o.l.

It seems if you have it in automatic, it stays in automatic despite taking the key out. Is this the case? How does one tell it is in automatic?

The system did have a hiccup shifting from 26*C to 22*C, so turned it to max cold which reduced it from hot air to warm, and cleared in a few minutes. Think part of the issue was the passenger floor vent was blocked with all the stuff in the wagen and had to clear the hot air.

Over all, I am trilled with the system! :D It is harder to fall asleep or get too cold, as on 22*C it is a nice soft cool air not some gale force that dries ones eyes out and causes icicles to form. The system is nice and logical, it doesn't have some abstract diagram showing warm to cold, it actually tells you what the temperature is! :D If you do get a tad sleepy, just move the wheel ever so slightly cooler and the fan will speed up and cabin will get colder. Grab something to crunch, and even more set. ;) A very fine highway auto.

Running the compressor for defrost is the standard method on all cars of any brand with ACC and even some with manual climate control. The evaporator removes moisture from the air. Very useful for defrosting a windshield.

In the Southeast, i consider working a/c a safety feature especially in the fall and winter. We get chilly rain and if you cannot dehumidify you will completely fog up on the inside in short order.

Operating the compressor frequently is beneficial to its longevity. If it sits idle the seals dry out and it will start to fail.

Side story: I have a 2004 Honda CR-V that has a manual climate control. There is electronics involved but you still have to choose the modes and temperature yourself. I found on a Honda forum an Easter Egg that lets you choose whether it automatically engages the compressor with defrost or not. For some reason the default setting is "disabled".::confused: