Hi everyone,

I purchased this vehicle a few months ago, and knew it had some kind of issue with the climate control. For a long time, the only symptom was that the air would blow on the windshield (defrost) and outer two dash vents. The car has known vacuum issues with the door locks, so I assumed that the climate control air direction was probably another vacuum related issue (possibly the bellows) and decided to address it at a later time.

A few weeks ago, another problem emerged - the Econ mode stopped working intermittently. I began reading online about cracks developing in the solder traces, so I decided to pull mine out and have a look. I discovered that a few traces have some burn marks! Also, in the process of taking mine apart, I managed to damage the switches so that the springs came off. From what I can tell, plastic around the switch came off which holds the springs on.

So I'm looking for advice on what to do here. I can't see any way of cheaply repairing the switches, and the burn marks have me wondering if that is the root of my intermittent Econ mode.

In the realm of buying a replacement CCU, is there a viable option for a used part? I've seen rebuilt ones online for around $200.

Thanks in advance for any wisdom!

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1985 Mercedes 300D 209K miles

I have seen rebuilt CCU 's on Ebay for $169.

This site has one for $167, which is the best price I've ever seen.

http://www.***************/

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1985 Mercedes 300D 209K miles

Before installing your new ccu, check your aux water pump. Make sure it is not stuck or else it will destroy your new ccu. Others put a fuse on one of the lines of the aux. pump. I dont recall how many amps.

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'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles

One amp. The water pump should draw about .6-.75 amps.

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'83 300D, 126K miles.

If you prefer to go used, there is a subforum on this board for used parts, "Mercedes Used Parts for Sale and Wanted." If you don't see someone selling a used CCU, you can post a 'want to buy' ad.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Thanks for the suggestions.

I found that the CCU is available directly from ProgRama and the price is hard to beat. $149 + 20 core.

ProgRama 123 830 12 85 Mercedes Benz Climate Control Unit

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1985 Mercedes 300D 209K miles

I grabbed the climate switch from a W123 at PickNPull for ~$10 a year ago. My problem was not reading the operator's manual for how it should work. I removed the aux water pump in my 85 and get plenty of heat with just a heater hose in its place, so no risk of frying the board if the motor stalls and less chance of a leak. I also changed to Evan's waterless coolant so the heater core won't corrode.

I have a spare CCU that you can have for free. I am pretty sure it works but no guarantee. Just email your address to me at BWhitmore2@earthlink.net. I will send it priority USPS but it may take a few days to get to you. Happy Holidays.

Wow, thanks! Email sent.

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1985 Mercedes 300D 209K miles