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Old 7th February 2020, 11:35   #17
SD1too
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Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

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Quote:
Originally Posted by Roverguest View Post
What I don’t understand is, people say fan “failure” although the fan clearly does work, as per when AC is requested or when the temperature hits 112 degrees.
Only your highest speed is working which triggers at 112 degrees. That is much too hot. You need the lower speed which triggers at 100 degrees.

The windscreen demist button test proves that the fan does not work when air conditioning is requested. Don't rely on auto mode for a diagnosis.
Quote:
Originally Posted by Roverguest View Post
If the fan motor brushes had failed and or worn out, surely that would render the fan motor inoperable?
No. On the 3 speed system there are 4 brushes. Usually the low and medium speed common earth brush fails first so you're left only with "high" speed which triggers at 112 degrees. But the motor won't be running at high speed because of the worn out brush. It will be running at medium speed. Your cooling system is running at low efficiency and liable to overheat.

Simon
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Last edited by SD1too; 7th February 2020 at 11:47..
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