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engine fan


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:welcome:

Start by checking the fuses B4 and C5 and then the relay.

Relay 8 is the is the engine purge fan relay.

It will be on relay support 2 which is behind the rear seats/carpet next to the DME.

Relay 8 will be in the second row - 3rd from the left.

Measure resistance between Pin 85 and Pin 86 on the relay - it should be about 75 ohms - if not replace the relay.

Last possibility would be a DME fault.

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:welcome:

Start by checking the fuses B4 and C5 and then the relay.

Relay 8 is the is the engine purge fan relay.

It will be on relay support 2 which is behind the rear seats/carpet next to the DME.

Relay 8 will be in the second row - 3rd from the left.

Measure resistance between Pin 85 and Pin 86 on the relay - it should be about 75 ohms - if not replace the relay.

Last possibility would be a DME fault.

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my fan no longer turns on when I park the car.

If I put power to it the fan runs, is there a sensor or something

I should be looking for? For now I pop the bonnet until it cools down.

Thanks for any help or suggestions

Hi,

That's a little vague to understand. I say this because the fan starts when the engine is running but it wont always stay running when you switch off the car. Mine will if its very hot outside, but we are in Scotland and that ain't all that often.

How long have you had the Car and how long have you noticed the Fan working when parking? What was your driving style just before parking up and how warm was the weather?

The Fan has a temp switch/sensor on the right hand side of the engine comp'. I will have to find mine for future ref'. but if the fan works whilst driving, fundamentally there isn't too much wrong. Is it running when your engine is running?

check the Fan temp switch/sensor.

Perhaps your engine comp't wasn't warm enough for the fan to switch on, especially if you have had a cooler spell or been driving it slower??

Frank

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After the engine shut down, for 40 minutes the ECU is taking care of the engine compartment temperature. As soon the temp. is reaching 172F it will start and stop to keep it under 172F... So the fan is triggered at 172. Same thing if the engine is running. The temperature sensor is located a bit aft of the recirculation blower on the right side of the engine compartment. May be the sensoris at fault or the plug is corroded. Pic show you what it's looks like..

post-29683-033685500 1278073529_thumb.pn

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After the engine shut down, for 40 minutes the ECU is taking care of the engine compartment temperature. As soon the temp. is reaching 172F it will start and stop to keep it under 172F... So the fan is triggered at 172. Same thing if the engine is running. The temperature sensor is located a bit aft of the recirculation blower on the right side of the engine compartment. May be the sensoris at fault or the plug is corroded. Pic show you what it's looks like..

Cheers JPFLIP,

I'm going to have a look for mine later.

Frank

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  • 2 years later...

I don't know why Porsche engineer decided to show it blank on the fuse location diagram but in the wiring diagram it is in fact a second power source for the engine compartment fan. The fuse B4 receive his power directly from the battery and the current distributor. Fuse C5 receive his power from the fuel pump relay. Why? Because this fan can run even when you switch the ignition off to keep the engine compartment temperature below 78 F and it does that up to 40 minutes after shut down. When the switch is selected to ignition the fuel pump relay his energized also the power is switch over (in the engine compartment fan relay) to the fuse C5 and ready in case of demand. The switch over is control by the DME or ECU.

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Thanks jpflip. Sorry for the confusion, I had been looking at the Carerra's diagram in that other post and needed to look at the Turbo's (it's in the Turbo's diagram so this must only be true for the Turbo?). This is very useful to know in the work you were helping me with earlier today. I am learning a lot more about the DME / ECU from this experience.

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