W124 climate control 2 stage shut off
 

Hi Guys,

When I bought the car (88 300ce) I discovered that whole climate control system can malfunction in 2 ways:
1) Non of the 3 buttons work when you press them, lights in corner are out, full heat is on.
2) All buttons don't work but lights at corner are on, also full heat is on.


As soon I shut off the car and restart the car everything works again, aircon is cold, heat is how you set the wheels.

Any idea what can cause this kind of problem or what to check?

Regards,
Tom

1. Check blower fuse under the hood. May look good but has hairline cracks. Replace it.
2. Climate control panel may be going south. About $25+ at Pic & Pull. Easy to replace.
3. In rare instances your ignition switch is bad. Bad contacts causes high resistance in blower circuit which frys the CCU circuit board.

All three happened to me!

I recently worked on a 87 560SL's climate control system that was behaving similarly. It was stuck in full heat with high blower speed. No button presses changed anything.

Quite often what happens with these older electronics is that cold solder joints form, capacitors fail/leak out/go outside of tolerance and you end up with strange behaviours.

I've worked on a number of climate control system where this was true.

I have actually resoldered climate control panel, also climate relay (they looked good).
Also one strange thing for me, my climate control panel starts (if it starts) working after and only after car has warmed up, when thermostat opens.
Is this normal to W124 or there is another problem related to this?

Are you running the system in "auto" mode when this happens? In auto and heat I think it will wait until you have suitable coolant temp to make heat before turning on...

Did you replace any capacitors while you were in there? you might have some bad/dead ones in there that might be hindering operations.

I don't have auto option. I have climate control system with 3 buttons - Humidity, Snow and recirc.

Hmm I've seen that style system in 190E's they had a manual fan speed slider.

It looked like this:

201 830 03 85 First Gen Climate Control W201 - Imgur

It had 3 stages of PCBs that needed resoldered/recapped.

Is that what yours kind of looks like?

This is my climate control panel, I think it's gen II and it seemst to be quite rare thing on market, I would buy new one if there would be one reconditioned for sale.

[IMG]http://i58.photobucket.com/albums/g2...ps6a4d1ac9.jpg[/IMG]

Thanks for posting a picture. I believe that is dual zone manual climate control, a european thing it seems. I've only seen a few in pictures. Looks pretty cool though!

I would be willing to bet that it suffers from the same cold solder joint type problems as its automatic cousins.

If you are interested I'd love to go through it, recap and reflow it for you.

Otherwise new/used would be your next best bet:
http://www.ebay.com/itm/Mercedes-OEM-w124-EUROPEAN-Dual-Climate-Control-Unit-124-830-04-35-/121146504010

That unit on ebay has EC (economy) button last, but on my one there is recirc button.
My connection on the back in also different.

I live in Australia, so it will be little bit costly to send unit there, but never know.