Aux. Cooling Fans, Disco I

[crodatz]

I have a 99 DiscoI and have an overheating problem. The cooling fans only come on when the A/C is on but not when the air is off. Are these fans controlled by the engine ECU or are they controlled elsewhere? Does any one know??? Thanks Chris

 

[davidz]

controlled by a two lead thermal sensor in front of the intake manifold, near the temp sending unit, senses water temp and kicks on the fans to compensate.

 

[BaldEagle]

i was under the impression that they are only supposed to come on when the ac is on unless you are majorly overheating. i think your overheating issue is caused by something else

 

[crodatz]

The overheating was caused by the aux. fans going out and a bad headgasket. Fixed that however the aux fans are controlled by the engine ECU and it is not sending a signal to turn them on. They only run when the air is on. We put in a manual switch so I can control them until I find a used ECU that works.

 

[BaldEagle]

well my aux fans never worked for a long time and i never overheated. the aux fans are only supposed to come on with ac on unless you are really really overheating....

 

[mikemeyer0]

The 2 fans in front of the radiator come on when the a/c is turned on and or when the coolant temp reaches an excessive amount (I forget the temp at that point). The fans will also run while ignition is OFF if the temp is at or above this certin temp.

 

[jec]

For a 95 D1 (don't know whether 99 remains the same), trip point for fans coming on with A/C off is 100C. They will also come on after engine shutdown and stay on for 10 minutes if fuel temp is above 70C or coolant temp is above 110C. Operation of fans for high coolant with A/C off is controlled by Fan Control Module, located behind the right hand footwell trim panel. Engine Control Module only comes into play when engine is off, and then it starts the fans by grounding the Fan Control Manual when the fuel or coolant temp sensors exceed the criteria above.

 

[peter sherman]

you didn't need a switch just unplug the compresser