Engine Cooling Fan Runs When Ignition is Switched to On Position and After Shutdown

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May 17, 2012 | 02:24 PM

BrickonBlocks

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Engine Cooling Fan Runs When Ignition is Switched to On Position and After Shutdown

I have a 1994 Volvo 850 Turbo.

My engine cooling fan runs constantly as soon as I turn the ignition switch on (before engine starts) and for a few minutes after shut down. This behavior is not related to engine temp. It can be stone cold and still the fan runs.

The temp gauge on the dash reads the correct temp and stays stable at about 3 o'clock once the car has warmed up.

The thermostat is good.

I replaced the ECT sensor and nothing changed.

I tried a different fan relay (from another 850 that works correctly), and that didn't change anything (not that I expected it would, but hey, I’m grasping at straws now).

On a hunch, I disconnected the ECT sensor (thinking I might have a wiring problem or something) and the temp gauge inside the car still operated normally. Is there another temp sensor that could be the culprit?

Any help would be greatly appreciated.

Thanks,

Jay

May 18, 2012 | 08:31 AM

rspi

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From: Albuquerque, NM

What state of operation is your ac in? Whenever the ac is turned on the fan is suppose to be on.

May 18, 2012 | 01:13 PM

BrickonBlocks

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The AC works. The compressor is not running all the time, but I'm wondering if maybe the switch that indicates that it is on is faulty.

Where is that switch located?

Thanks for the input,

Jay

May 18, 2012 | 01:53 PM

rspi

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From: Albuquerque, NM

I'm not sure but I was asking about the AC to see if it was on. Turn ALL of the controls for the AC off and see if that changes anything.

May 20, 2012 | 06:48 PM

Kiss4aFrog

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From: Cape Coral, FL

If the AC is turned on or if the defroster mode for the windshield is selected the cooling fan will be powered on all the time the ignition key is in the run position or the engine is running.

May 20, 2012 | 07:45 PM

Turkey_Sandwich

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I don't know how your dash temp gauge operated normally with the ECT disconnected??? It is the sole sensor for temperature. The ECU controls the fan relay.