How to force Radiator cool fan on high - towing..

[Porsche-FV]

Greetings,

 

I have 1 09 Cayenne S, that I tow my race car around with, issue is, the large front cooling fan only runs a low speed. If I click on the A/C, I the fan runs on high, but towing with the A/C is not a great idea either.

 

Is there a way to force the fan into high? I an handy with electronics, I was looking for a high speed relay, something I can feed a trigger to, to force the fan high. but not sure where that may live, or other ideas?

 

Thank you,

FV guy..

[JFP in PA]

1 hour ago, Porsche-FV said:

Greetings,

 

I have 1 09 Cayenne S, that I tow my race car around with, issue is, the large front cooling fan only runs a low speed. If I click on the A/C, I the fan runs on high, but towing with the A/C is not a great idea either.

 

Is there a way to force the fan into high? I an handy with electronics, I was looking for a high speed relay, something I can feed a trigger to, to force the fan high. but not sure where that may live, or other ideas?

 

Thank you,

FV guy..

 

Your radiator fans are controlled by what is call plus width modulation, which is built into the fan motor itself, and therefore rather difficult to modify.

[Porsche-FV]

Hi,

 

Thank you JFP, I was thinking that as it does kick on high with AC, or defrost for example, something is telling it to do so, PWM is fairly common these days.

 

I have seen posts about Radiator fan relays in other posts was just hoping to force it high without doing a diode and relay..

 

like this: |PWM|-> Fan motor, I would |PWM|->Hi_Current_Diode->12VTap->Fan motor   apply 12V from additional relay to the tap, the diode prevents back current from cooking the PWM, hmm, might add a second to remove the pwm all together..

 

But I was hoping to just trick a relay to force fan high..

 

Perhaps a better question, why is my fan not going high when it starts to creep past mid point?

[JFP in PA]

1 hour ago, Porsche-FV said:

Hi,

 

Thank you JFP, I was thinking that as it does kick on high with AC, or defrost for example, something is telling it to do so, PWM is fairly common these days.

 

I have seen posts about Radiator fan relays in other posts was just hoping to force it high without doing a diode and relay..

 

like this: |PWM|-> Fan motor, I would |PWM|->Hi_Current_Diode->12VTap->Fan motor   apply 12V from additional relay to the tap, the diode prevents back current from cooking the PWM, hmm, might add a second to remove the pwm all together..

 

But I was hoping to just trick a relay to force fan high..

 

Perhaps a better question, why is my fan not going high when it starts to creep past mid point?

 

The PWM is triggered by a signal from the DME, which gets the coolant temp from the same senor that operates the dash gauge.  As these dash displays are well known to be both non linear as well as flat out inaccurate, I would suggest reading the DME temp by connecting the car to a Porsche specific scan tool.  The car may not be as hot as the dash makes you think it is.........

[Porsche-FV]

Interesting...

 

This is the exact opposite as a BMW gauge, which always shows 50% if it moves north, its already way hot..

 

Perhaps I have a excuse to buy a ScanGauge now.. 😉 or just use my obdii tool, then I have been lusting over the durametric ....

 

I will report back if I find anything good!

 

Thanks JFP!