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Old 03-19-2009, 10:20 AM
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Cal Learner Cal Learner is offline
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Join Date: Aug 2006
Location: Marysville, CA
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Quote:
Originally Posted by Arthur Dalton View Post
...the high will only have a demand when the coolant temp reaches 105C and the low only gets a demand when the a/c high side pressure gets dangerously high ... That is why they are AUX FANS, They come into play when a taxing condition presents itself. A quick test in your case is to simple turn key ON and pull the 2 wire connector off the blue sensor on the termo housing...that will default the ACC Panel to High Fan, verifying that circuit as OK.
Your explanations have probably helped a whole generation of MB DIYers by now. Thanks. By installing Jim F's Cool Harness on the thermo sensor, I guess all I'm doing is putting a second identical thermistor in series with the existing CTS, and that's enough added resistance to lower the temp threshhold for fan activation. Is that about it?
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1988 California version 260E (W124)
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Past Mercedes-Benz:
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1959 220S Introduced me to the joys of keepin' 'em goin'

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