DIY page. Introduction to Resoldering Climate Control Unit - Page 5 - PeachParts Mercedes-Benz Forum

SD Blue · #1 08-20-2008, 01:27 PM

I believe your car has several differences from the original W126's so you will need a little different information and schematic. I believe this may be a procedure to help you diagnose your particular vintage: ac still not working after ac conversion 87 300SDL

James80 · #2 08-21-2008, 07:54 AM

thanks for your quick reply. I think that link is mostly to do with problems with the air conditioning not working at all and I don't know if it will help work out what system my car has. but I can all ways check every thing on that list

this is a picture of my push-button control unit

SD Blue · #3 08-21-2008, 11:59 PM

I believe the temperature controller is located above the passenger footwell. Do you have a copy of the factory service manual or more specifically, the schematic for your car? IIRC, yours has a small sampling fan that draws air across the sensor for better response to temp. changes. Also, the pushbutton controller was changed in 85 or 86 to a new version.

Another note, have you checked the fuses? The aluminum ones are notorious for causing intermittent problems. Use the copper ones if you can find them.

You might find someone in the Tech Help section of the forum that is more familiar with the nuances of the later 126 series climate controllers.

calvertg · #4 10-01-2008, 06:59 PM

My '81 300SD climate control isn't working and I've checked the fuse and blower motor and replaced the control unit with a questionable one. It worked for a short period then stopped. Winter is coming to Iowa so I thought I'd try resoldering the board but couldn't load the DIY page. Could someone send it to me? Thanks a lot.

SD Blue · #5 10-02-2008, 12:08 PM

Quote:

Originally Posted by calvertg

My '81 300SD climate control isn't working and I've checked the fuse and blower motor and replaced the control unit with a questionable one. It worked for a short period then stopped. Winter is coming to Iowa so I thought I'd try resoldering the board but couldn't load the DIY page. Could someone send it to me? Thanks a lot.

Describe "isn't working". Typically, resoldering is for symptoms of no mode change, ie. defrost only. If you just aren't getting heat then the usual culprit is the monovalve.

egebjerg007 · #6 11-09-2008, 10:53 AM

Hi
could this also apply for the cliamte control panel of W116 , 300SD ? I also only have warm defrost and no other knobs are working. Can not regulate heat either.

SD Blue · #7 11-10-2008, 10:14 AM

I believe the W116 is different, and I'm not sure about the Euro model, as they have the servo. If you do an advanced search for "servo" here on the forum, you should be able to find more information. Especially check the DIY section articles that come up in your search results.

(Advanced search is found under search on the header bar at the top.)

egebjerg007 · #8 11-15-2008, 11:59 AM

Thanks, I´ll search. It´s a US model returned to Europe.

Addgod · #9 02-24-2009, 04:59 AM

Ok I have run into one of the problems you describe in here.

Quote:

Another common problem is that the climate control only seems to work on max or min values, quite often this can be attributed to a disintegrated foam hose which runs from the dash to the temperature sensor for the climate control.

Does anyone have some pictures or something that can guide me on my way, to find this foam hose, so I can figure out if it has been crushed?

It should be said, that my car is a 1987 300 E Euro model, with a manual dual zone system. One for the drivers side, and one for the passengers side.

Thx.

Addgod · #10 02-24-2009, 08:50 AM

Never mind, found it and it seems to work fine.

There is suction, it is not a whole lot, but it is there.

But that just leaves me even more baffled, but now it is time to do some measurements on it, to see if actually works.