I have a 94 855 turbo and the enginecooling fan won't turn off. I changed the fan relay and it still has the same problem. With an electrical meter i noticed that the #1 remote cable is always sending electricity to the fan relay. Hence i think is the ECU but i am not sure, plus the ECU only tells me (by codes) faulty low fan speed. Also the car has a small short circuit that nobody finds. Please Help! (sory for my english I' am from Puerto Rico)

 

Maybe the Coolant temp sensor is bad keeping the fan on.

 

So you suggest i change the part....but im still thinking why the ecu doesnt detect it?
And why if the engine switch is off can it still send a wrong signal to the ecu?

Il'l chek it out...
Another question someone knows if the ECU controls the rpm gauge and the engine temp. gauge? because both failed when my fan failed....

Sory i know i should wrecked it but is my only car

 

They might be connected. I would change the ECT and thermostat and see if that fixes it.

 

I'll do it. Thanks

 

Please let us know how it goes.

 

If the ECT sensor was faulty, it can send wrong signal to the ECU and then the ECU keeps the fan running even after the key has been removed.

I would try locating the short circuit first. If there is a short circuit, it could fry something you replace/repair.

See attached for the instrument gage testing details.


JPN

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The last page.


JPN

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Did changing the ECT Sensor work? When the sensor on my sons 850 went bad, thge running cooling fan was one of the symptoms