This sounds exactly like what is happening.

tobybul, I have watched a CD-ROM on removing it, { available from Repairflix.com } pull ashtray, there are 2 screws, remove, pull whole unit out, might have to unplug an item or two. On the radio bottom there are two "tangs" two little things, pull down and slide toward rear of car, unplugging what you need to. Using a stubby phillips screw driver, remove two screws, the wood laminate will drop down slightly and lift out of the way. The switches push out from the back, if you need to deal with them. Then you will be able to see two bolts, on the upper sides of the CCU, they screw into plastic I think. Remove, and you should be able to pull out the assembly. I went to the local pick'n'pull today and saw three CCU boards that were seriously fried, albeit not on a 126, or 123. Other posts seem to cover these problems. Hope this helps.

If you need brushes for your motor, Bosch is not allowed to sell them per their contract, so MB can make more money from you. However, I did read once that you can get brushes made up from almost any vacuum repair shop!
Good luck.

Once you have the box out, on the underside at back you will see, usually three plastic "tangs" you need to push in and toward front, and cover should "pop" out, a pocket knife or similar tool is utilized.

I bought a new fan motor and new aux water pump and a used control unit. I'm going to replace the pump tomorrow. I have the article on how to replace the water pump but its a little vague.

Does anyone have any picture, tips or things to look out for?

All folks should become familiar with this little 4 step process:

Click on "Search"
Select "Advanced Search"
Type in Subject..........
Select "DIY Links by Parts Category"

WHunter has done a lot of work putting this together. Usually there are photos and several posts that cover the different models.

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Sam

84 300SD 350K+ miles ( Blue Belle )

All folks should also become familiar with reading the original post. I said I already had that article and it was a bit vague. I was looking for extra info, extra pictures or tips not listed.

Sorry, I'm not familiar with what "that" article is, as there are at least three of them. In your defense, the third one (mywebpages) that has the most detail is not currently a working link.

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Sam

84 300SD 350K+ miles ( Blue Belle )

On the DIY Articles page, there is only one auxiliary water pump replacement article that I know about.

Replacing the pump looks daunting because you can't see it. But, if you remove the section of the forward firewall, the job becomes effortless. The pump becomes visible immediately and you simply disconnect the hoses and replace the pump.

Removing the battery is preferable to give you some additional working room and to easily access the connection plug.

Get the shopvac out and clean the area below the pump before installing the new one.

Is it advisable to put the 1 amp fuse on the pump side or the car side of the connector?

Sorry, but I think you may have thought I was being demeaning or something. When I reread everything, I did not do a great job of coming across. What I meant was try the search in combination with DIY and its easier to find all of the articles.

There was a post, done by Carrameow, that had excellent photos and including a lot of step by step instructions. For some reason the link to the photos is not working.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Put it on the supply side. The brown wire is the ground (car side).

Ok, so today, I replaced the aux pump, the blower and the acc (ccu?). No blower....I suspect that the ccu I got from ebay is bad. I don't know what else it could be.

BTW, the aux water pump took me about 1/2 an hour. I must be lucky. Everything came off easily and had no problems. The pump was frozen so I'm sure that I didn't waste my effort there. Had I known that I could just unplug the pump, I would have done that.