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Old 08-06-2005, 10:05 PM
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Need AC and tach help PLEASE

My 87 300D turbo has started to have an intermittant tach and AC operation. the fan still blows but the cold only comes when the tach is working. Both will stop at any time and only sometime start after the car is restarted.


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Old 08-06-2005, 10:42 PM
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Location: Metro Detroit, Michigan
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Ground wires and fuses

would be my first guess.
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Old 08-06-2005, 11:50 PM
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both seem OK

I cleaned both Battery posts and the ground point and it was back briefly, but went away again. Fuses look fine.

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Old 08-07-2005, 09:10 PM
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Join Date: Dec 2003
Location: Metro Detroit, Michigan
Posts: 17,357
Smile Help

Need pictures under hood, to evaluate possible issues.
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Old 08-07-2005, 10:20 PM
Coming back from burnout
Join Date: Jun 1999
Location: in the Pacific Northwest
Posts: 2,274
I am having the same exact problem....

Do a search under KLIMA relay
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Old 08-07-2005, 10:25 PM
Join Date: May 2002
Location: Blue Point, NY
Posts: 25,396
The Klima relay takes a speed signal from the tach. It compares this speed signal to the speed of the compressor and, if they match, it keeps the compressor engaged. If they don't match, as in your case, because there is no tach signal, the Klima will dump the compressor to protect the serpentine belt.

So, you need to track down why the tach signal is intermittent. When you fix this, the a/c will function properly.

It has nothing to do with the Klima directly. The Klima is simply not getting a tach signal.

If you can't fix the tach signal, there is a way to bypass the Klima via the use of a cobbled up ice cube relay. I just did this myself, today, to eliminate the Klima from the entire diagnosis.
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Old 08-08-2005, 01:50 AM
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Thumbs up working again-many thanks

I searched the site and found the Klima (wasn't he a hockey player for the Red Wings and Oilers) it took a while to identify it. So I cleaned it and all ground wires and then cleaned the area and all wiring around the AC compresser. I used an emory on anything not clean and shiny. After several tries and more tweaking tach and AC are working again, thank God as I am on vacation in the badlands of Alberta 100F (no multimeter, just battery post brush, brake clean and my wifes emory board)

Thanks again

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Old 08-10-2005, 03:10 AM
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Back to not working

How do I check the tach signal? she crapped out on me but gave me 42.5 mpg highway (Imperial gallons 4.54Litres vs 3.78liters US gal.) on my ride home


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