Coolant Fan Stays Running Until Battery Dies? Help

[RUM4MO]

Okay, so you unplugged the connector with the heavy wires from the fan controller when the car was cold and the thermal switch connector was still unplugged, and the fan running at slow speed stopped. So maybe repeat that everything in the same state, but this time, instead of unplugging the connector on the fan controller with the heavy leads, unplug the one with the thinner leads which is the control connector, if unplugging that leaves the fan running on the slow speed, then it has to be the controller assembly/module.

 

[Ibiza08L]

Okay, so you unplugged the connector with the heavy wires from the fan controller when the car was cold and the thermal switch connector was still unplugged, and the fan running at slow speed stopped. So maybe repeat that everything in the same state, but this time, instead of unplugging the connector on the fan controller with the heavy leads, unplug the one with the thinner leads which is the control connector, if unplugging that leaves the fan running on the slow speed, then it has to be the controller assembly/module.

I think I unplugged the smaller connector and it turned off. I didn’t touch the bigger connector today

 

[RUM4MO]

Well, in that case, if it was the connector with the thinner wires, I'd hold off in ordering in another controller as it sounds like something else is switching that fan on.
Maybe try unplugging the AC pressure sensor connector from the gas pipe on the RHS of the car, on the inner wing area. There are only 2 alloy pipes and only one of them has a pressure sensor on it.

 

[Ibiza08L]

Well, in that case, if it was the connector with the thinner wires, I'd hold off in ordering in another controller as it sounds like something else is switching that fan on.
Maybe try unplugging the AC pressure sensor connector from the gas pipe on the RHS of the car, on the inner wing area. There are only 2 alloy pipes and only one of them has a pressure sensor on it.

Unplug the pressure sensor when the low speed is running and thermal switch is unplugged? In other words, the same state as before?

 

[RUM4MO]

Unplug the pressure sensor when the low speed is running and thermal switch is unplugged? In other words, the same state as before?

There are only 2 sensors that when the system is working properly, can switch on the radiator coolingfan(s), one is the pressure sensor on the AC pipe, the other is thermal switch on the radiator, if you remove both of them while the fan(s) is running, the fan must stop.

 

[Ibiza08L]

There are only 2 sensors that when the system is working properly, can switch on the radiator coolingfan(s), one is the pressure sensor on the AC pipe, the other is thermal switch on the radiator, if you remove both of them while the fan(s) is running, the fan must stop.

Ok. I will get it in the state where the thermal switch is unplugged and the low speed is on and sticking. Then I will unplug the AC pressure sensor. I will try this on Sunday and feed back.

 

[Ibiza08L]

There are only 2 sensors that when the system is working properly, can switch on the radiator coolingfan(s), one is the pressure sensor on the AC pipe, the other is thermal switch on the radiator, if you remove both of them while the fan(s) is running, the fan must stop.

Did this. Fan stayed on?

 

[RUM4MO]

So, that only leaves a wiring problem, a controller problem or the car is sending out an incorrect "slow fan on" request.

I know that reaching in and unplugging the "demand" low current plug from the fan controller will not be easy, but with everything else left plugged in, unplugging that would need doing when the fan remains on, to point the finger at the fan controller.