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.

Those bulbs might not be the same wattage. I've melted a housing here and there using non-MB bulbs.

I'm currently trying to figure out how to put LED's in place of those little buggers. Need a 12v source to hook them up (that won't toast them also) to and I'll be set.

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Gil

2004 ML350
1984 300CD; Ivory (sold)

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.

__________________

Disassemble the unit and check for cracked joints. There are two "wing" boards that contain the cable plug pins and are soldered to a mainboard forming a shallow 'U' shape. Then, there's another daughter board stacked with the main board -- so there's really four boards in all. I recently did mine and found that the solder joints to one of the wing boards were broken clean through.

Incidently I did a bit of root cause analysis on my CCUs solder joint failure (not that I'm necessarily qualified) and concluded that the wing board in question was soldered on at an angle, and then flexed to make the connections meet at the far end. A poor design (solder as mechanical attachment) aggravated by poor manufacturing (a flexed wing board adding additional stress). The CCU unit plastic case provides the gross mechanical strain relief for the wings, but this kind of stress didn't wasn't something it could provide the strain relief for. This might explain why these things fail if others were manufactured incorrectly like mine was.

Others have reported the switch solder joints to have failed, but mine were fine. All the cracked solder joints of interest are inside the plastic case, and there's a couple of stacked boards, so just getting to the bottom of one of the boards isn't enough.

I took copious pictures of the CCU disassembly procedure, problem, what cracked solder joints look like, etc., but I don't have time to upload them tonight (sorry), I'll try to get to them tomorrow.

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'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

i didnt see any shallow u-shape joints on the inside, i fixed all joints, in and out, plus the fan speed controller and temp wheel(just figured it out after some looking). but the plug pins i left alone because they didnt seem to be under stress, burnt or cracked. but are these what your saying will fail? mine still will not work any differently so im thinking i should try those...

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Here's the pictures I promised on how to disassemble the ACC unit...


remove the temperature unit and the cover off the fan buttons so can remove the buttons by psuhing from behind. Plastic tabs are delicate after 20 years, so careful not to break. Use penknife to slip between plastic tabs so they can be gently popped apart (ie. don't cut the plastic with it). With fan button unit cover removed, pop three fan buttons off from behind.




Pop front loose. One tab on top, two on bottom (circled in blue in previous two pictures). The front can't come off because the buttons hold it on. I couldn't figure out how to pull them off, so I did this in order to...


Reach in behind the front with a penknife so can et behind each button and pop it forward off its switch.

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'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

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.

i went the cheaper route and got a 85 300D ccu for about $50 in a junkyard, that also did the same meaningless tasks of making a couple noises when a button is pushed. the one i repaired was the stock 81 280CE ccu. not sure if im ready to shell out that much

__________________

This might be your pet peeve
Check this out....You just never know!

pictures? i like pictures i just disassembled it and got to every connection except the actual external pins cause that looked like alot of work.

that is a strange find bens lover, that should be in the climate control diy section. if i figure out how to get the cover of that harness off i will take a look.

edit: i just tried looking for the wire in the picture, i didnt have it, and the covers were a real mess to get off....
actually two on that harness were not used

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Hey everyone, I thought I would add something to this thread I recently "resoldered" my one climate control in my one w126..

I resoldered the joints that connect the 3 PCBs...

I also retouched the solder on the thermostat knob, dragged some down the lines that connect the knob to the pins..as well as the stuff on the fan switching side..

I also completely removed the switches PCB, checked for anything broken on it. Apparently the resistors/diode was replaced at one point in time..

I saw a couple traces that looked like they had veins running throu them or something. I decided to grab a screwdriver scrape off the material and lay down some solder in place of it.

I tell you what, I've never seen one of these control things work and change settings and whatnot this fast before. I rolled the temp wheel from cold to hot and as soon as I hit the red relays were clickin and the fan was motorin..

impressive.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

Greetings:

My Little Old Lady, a 1987 300 SDL, is servicing all my needs, except the climate control.
She will start up dutifully on any Morning, however, the climate control will not start. No blower motor, no air-flow, no nothing. As the motor will warm up, HOT air will flow under the windshield, even though the blower motor is not running. You can push any of the climate control buttons, nothing will change. The HOT air will flow at the windshield, but nowhere else. You pull over the road, because you are frying, turn off the motor. Then, you start her again. LO AND BEHOLD, the climate control system is working as it was designed to work!!!

What do you think???

Of another note:
where can I buy repalcement seat cushions for the 1987 300 SDL?
OR: what alternatives are there to get the firm cushion back?
After all, she is 20-years old, 189,000 miles, IN PERFECT condition!!!
I would like to re-inforce the seat cushions.

Thank you for any and all advice,

marozsanjanos@hotmail.com

J.M.

Ok, after several hours of surfing I found this site and registered. I now know I need to replace my blower brushes, rekit the mono valve, and resolder the CCU. I understand there is a resistor in the blower circuit that could also be part of my problems. Where is it and how do you diagnose, repair, replace, or ?

There haven't been any recent posts to this thread, I hope it's still found.

Charles

The "resistor" is a metal box with wire coils; it sits on the passenger (right) side inner fender. Although anything can break, I've not heard of any actually doing so. The climate control problems that get the most play here are
(a) resoldering or replacing the pushbutton control unit,
(b) rebuilding or replacing the monovalve,
(c) rebuilding or replacing the auxiliary water pump (remember to add a fuse),
(d) replacing the brushes in the fan motor or replacing the entire motor (my brushes had worn into the commutator so much that I had to replace the motor),
(e) replacing the disintegrated foam tube that connects the interior temp sensor to the blower intake, and
(f) rebuilding, replacing, or working around failed vacuum pods (that move the doors to direct air here and there).

This does not count repairs to the refrigeration system, which can be a whole set of problems by itself, nor does it cover bad thermostats, clogged radiators and heater cores, and other parts of the engine coolant plumbing.

Mercedes designed the climate control system to default to "hot air to the windshield" as a safety measure, so you could always get your windshield clear of moisture, ice, etc. If you have a problem where that occurs sometimes but not always, the electronics are probably getting flakey. Someone here probably has had that exact problem and can tell you what to do.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970