Hi!

I bought an 85 300D Turbo two days ago and I am already having some problems that didn't exist when I drove the car home. I have been able to solve or at least figure out most of them through previously posted info. but this one is stumping me.

The climate control, which worked well just two days ago, will now hardly work at all. Once in a great while it puts out just a little bit of air for a short time, and today when I turned the key to '2' it was working full-blast for a couple of seconds and then stopped.

I don't know quite what to make of this, so if anyone has ideas they would be appreciated!

Thanks.

There are two manual speeds for the blower, top and bottom buttons too far right. Center small button between them is auto. Try the manual speeds. Also try far left button--this is defrost and overrides other controls.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Sounds like the climate control unit. I believe there's an article on
how to rebuild it in the DIY section. The 85's ccu is easier to rebuild
than the one on later models. Or you can buy a rebuilt one in the
200 to 225 range.

See what happens when you put it on defrost.

Bill

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_______________________________________
1988 MB 560 SEL 138k - Desert Taupe w/ Cream Beige Interior.

Mods:
Euro Headlights w/Smoked Corners
New seats from a `91
ASA 15-Hole Replicas
Sony HU, JL Audio 400/4 Amp, JL Audio 2-way Components on rear deck, JL Audio 3-way Components in door & dash.


2000 BMW Z3 2.3 Roadster 33k
2002 Toyota Rav4L 50k

Ahh!

I hope you're wrong, Gigtime. I will try moving the key a little.

It doesn't seem to make a difference whether I have the fan on high, low, or auto. I believe it has actually been on defrost the couple of times it has briefly worked again.

Thanks a lot for helping me out, everyone, and if there's anyone else with ideas I wouldn't mind hearing them.

Oh yeah - is there any difinitive test that would prove it's the ccu?

Obviously if the key thing works than it's the ignition switch, I suppose, and I understand that's a relatively easy fix.

Well, you won't like the "definitive test" I've used. I've replaced every
other component of the system and that's the only thing left.

Actually I did need a new compressor and other parts but I replaced the
blower motor and regulator and I now believe I didn't need to because the
CCU is the culprit for my current problem, which btw, is very similar to yours
with the exception of the key thing.

My AC comes and goes on it's own usually at random intervals and it never
stays on longer than a few minutes. The only cause and effect related action
is if I adjust the temperature while it's cooling, it will go off within a second
or two.

I would try the re-soldering technique recommended elsewhere on this site
if I were you. My car's an `88 and that method isn't that effective with my
CCU because you can't get to all the circuit boards in those units. With the
85, you can.

Bill

__________________
_______________________________________
1988 MB 560 SEL 138k - Desert Taupe w/ Cream Beige Interior.

Mods:
Euro Headlights w/Smoked Corners
New seats from a `91
ASA 15-Hole Replicas
Sony HU, JL Audio 400/4 Amp, JL Audio 2-way Components on rear deck, JL Audio 3-way Components in door & dash.


2000 BMW Z3 2.3 Roadster 33k
2002 Toyota Rav4L 50k