Peter_964C2

When I stop the car after a (short) ride, a few seconds later the rear blower starts to blow. Most of the time the blowers stays on for 10-15 minutes. (I think he blows at high speed at that moment)
Is this a normal behavior ?

I've replaced the relais because he was broken and replaced the PTE and the registor as well at the same time

Christoph964

Hi Peter,
I assume you mean the blower at the left top end of the engine. Check, maybe using a Bosch Hammer or so, for any failures. Maybe the "pre-resistor" is dirty or broken down. This pre-resistor consists of a PCB, a coil, a capicitor and a bi-metal switch. If possible try to clean it using "electral cleaner" or so. If it's broken a new one will cost approx 100 Euro at Porsche Service
Good Luck
Christoph

DarrylH

The rear blower is intended to come on if the temperature in the blower ducting is too high. If the blower comes on after only a "short drive" then it may be that the temperature sensor is sending the start signal at too low a temperature, that is, it may be failing. If so, it's cheap and simple to replace. Both the resistor mentioned above and the temp sensor are in the tube downstream of the blower itself, easily seen sticking out of the tube.

Peter_964C2

I replaced both parts that are in the tube, the resistor and the PTE (temp sensor), at the same time of the relais with new ones.
Where can I find the pre-resistor ? Part number ?

DarrylH

Ah, sorry, I misunderstood. This is with the key out, correct? It is possible then that it's behaving normally - how hot is Ypres at the moment? Or even if it is coming on at a lower than normal temperature, there's no harm done as long as the fan turns off as it should (except a bit off additional battery drain...)

Peter_964C2

Hi Darryl,

The blower stays on after shutting the motor down,.. but the key in the most left position still in.
How hot in Ypers ?? It's never hot here :-). We are happy if it doesn't rain.
No.. serious now.. yesterday the temperature outside was about 24 degrees C and I drove about 10 kilometer. The blower started a few sec. after I stopped the car, and 10 minutes later the blower stopped.
Is there a differance between key out and key in ?

DarrylH

There's a difference between key on and key off. The threshold temperature to start the blower is lower with the key on, by quite a bit. That's why you'll often hear the blower start up when you turn on the key before starting the car if the car has been driven recently. However, with the key off, the normal behaviour is for the fan to come on only when the blower plumbing is very hot. It sounds as if your car is working correctly, but that the blower is coming on at a lower than expected temperature. That may actually be a good thing except for the additional wear on the blower motor and drain on the battery. If your resistor and temp sensor are working properly, unless someone has a better idea, I might not worry about it.