i have resoldered mine several times on several different cars. it's a common problem. i'm not so sure it's vibration that causes the problem though. it may be the component on the circuit board itself. some components get warm when in use. the warming and cooling will crack the solder joint. i repaired my mig welder that had the same problem. i've also repaired 2 of my t.v. sets, same thing. no vibration on the t.v.'s. just cracked joints from the heating and cooling of the individual component. with the expansion and contraction the solder gets work hardened and fails. much like bending a piece of metal back and forth until it breaks. that's my 2 cents. J.O.

Jeff aka boostnbenz, you had mentioned that the switches can be purchased. Do you mean from like Mouser or something?

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

I just removed the unit and have it totally disassembled. I think!?

Does the black plastic case which holds the boards come apart?

I think, from the thread, that I just solder the ones that look brown or loose. At first sight, everything is ok so I'm wondering if this will fix my CCU.(replaced my ignition switch because the CC goes off and on when it wants to.)

I'll solder what I think is bad and put it back together.
One more thing. The 'AUTO' button falls out. I don't really see anything holding it in except a small ridge on the bottom of the button?

__________________
Rick & Michele in California
1985 300SD Turbo Deisel
300,000+ miles

1963 Mercury Meteor Stationwagon
1959 Montgomery Ward Silver Pigeon Scooter & matching bicycle
1974 IH Scout 4x4

Yes, It rotates out in relation to the switch buttons (push)

solder them all, and expecially where the two boards meet. Brown is a good clue.


The button is black, it has a white inside with two tabs, are they broken or there. You can buy just the buttons from MB

AUTO BUTTON 123.153
A1268211758

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

Thanks omegabenz, that helped me a lot.

Well, i put it back, or actually just connected the power to it and it seems fine. I'll see because this is what happens. First it will work and after 3-5 min. it will shut off for good.? Hopefully my solder job did the trick.

My other question is about the set of 5 lights connected together. I put the lights on and none work. I don't think that they did originally so I'm going to the Benz dealership to buy them. I have some lights with the white body only that looks like its own socket, plugged into two male electrical fittings? or ones that have that white fitting that sit in a black plastic male socket.

Either way, do they just 'pull' out or what? Do you think they will have them in stock?

__________________
Rick & Michele in California
1985 300SD Turbo Deisel
300,000+ miles

1963 Mercury Meteor Stationwagon
1959 Montgomery Ward Silver Pigeon Scooter & matching bicycle
1974 IH Scout 4x4

Could you post a picture of your question?

Go to checker, autozone, etc, they have the bulbs. They are very small.

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

When resoldering these old high current connections, I find it useful to use solder wick (a braided copper material) to remove as much as the old solder as possible, or a solder sucker. Then use new solder for the connection.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

SYLVANIA 2721 BULBS (I just got some at checker), you need at least 5 bulbs

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

Here is a picture of a bad solder joint before repair. It is the best resolution I could attain. The black ring surrounding the joint is an open crack visible with my 18X magnifying lense.

Attached Thumbnails

 

__________________
http://i284.photobucket.com/albums/l...aman/Fleet.jpg

Peach Parts W124.128 User Group.

80 280SL
85 300SD
87 300TD
92 300D 2.5 Turbo
92 300TE 4Matic

Back when I wrote that a few years ago there were several online parts places which sold just the fan speed switches for the CCU, it was the white body with everything inside of it. I don't recall if they had the temperature control knob available separately or not.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

They are available here on mercedesshop as well.

I resoldered the board twice, and examined it, but I am still haveing problems. I took everything apart and cleaned it, etc.

for the w124.133 board, its working great now, but for my w123.153 I cant seem to get the climate control to work properly. Should I check anything else?

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

Did you resolder the pins where the side harnesses connect to?

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

yeah, I tried to, but that solder is very hard.

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

sorry to bump this thread, but it seems to be the main dicussion on this.
i just re-soldered every joint on my ccu and it performs the same task as before, just opening vents, letting heat through on defrost, but still no blower at any setting.

im not sure if i have to get inside this unit, because it explains three ccu boards but only has pictures of the unit assembeld.

what still needs to be checked on this board before i move onto other possible problem areas on the car?

my heat/ac has worked for multipe months at a time perfectly so this makes me think its something electical.

__________________

I tried resoldering several times three different push buttons, but no dice.

I bought a rebuilt one guarenteed for 3 years from programa (cost me about $225 at my wholesale discount).

I just need to send back the core ($50 core charge ontop of the $225). I was sick of messing with it.

The programma unit works very well thus far.

Austin

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.