Hi, i have a Cayenne s 4.5L 2003

My Cooling Fans are not working if the engine get to hot.

My Dashboard Water temperature meter shows the correct temperature . also via Torque and with my durametric cable the car knows the right temperature.
but its not engaging the fans.
But when i put my airconditioner on LOW LOW . both fans start spinning and cooling the engine.
fuses 1 2 10 and 12 are okay.

when i look into the wiring diagram i see that everything is controlled by the AC control unit
so that is able to control the fans but wont do it when the engine gets to how.

any idea where i can search. or what the problem is.


kind regards

Johan



Attachment 1371020

 

Most cars have a temperature switch in the cooling system to activate the fans. Don't know where it is in the cayenne but probably in a corner of the radiator (928s) or in one of the cooling lines (Audi Q5).

 

What do you mean with switch.
I checked the wiring diagram and dont know what you mean.

a physical switch a temperature based switch. or electrical like a relay.

 

A temp sensor that is a switch. When a certain temp is reached the switch closes creating continuity and sending power through the wires. Since your fans work with the AC on, the fans themselves are fine. If there's a cooking system temp switch and it's not closing, the fans won't come on. If you can find where that switch or sensor is, jumpering the 2 wires going to it should turn the fans on. If so, the switch is bad.
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