cooling fans - Printable Version

cooling fans - Printable Version

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cooling fans - xrad - 05-09-2009

Both fans come on below the upper hash mark and turn off before the lower hash mark. I replaced the temp sender and fan control relay..no change

I tested the wires at the temp sender and one will turn on one fan and the other turns on the other fan independently.

So.....is there a manufacturing error in the temp switch???? I have a brand new temp switch and one that is afew years old and BOTH do the same thing. AC is off when testing.

Anyone else have any ideas??

cooling fans - flash - 05-09-2009

did somebody stick a single speed 944 fan temp switch in there?

cooling fans - xrad - 05-09-2009

three prong plug and three prong temp sensor...how can you go wrong....

cooling fans - flash - 05-09-2009

i'm not sure but i think they are both 3 prong - i've heard of people putting the wrong one in there and having problems with the fans only running on one speed

cooling fans - jaap - 05-10-2009

QUOTE (xrad @ May 9 2009, 02:12 PM) <{POST_SNAPBACK}>Both fans come on below the upper hash mark and turn off before the lower hash mark. I replaced the temp sender and fan control relay..no change

I tested the wires at the temp sender and one will turn on one fan and the other turns on the other fan independently.

So.....is there a manufacturing error in the temp switch???? I have a brand new temp switch and one that is afew years old and BOTH do the same thing. AC is off when testing.

Anyone else have any ideas??
I don't see what is wrong with this. On my car both fans come on as well. Only when the temp does not come down when it reaches the upper mark (eg in traffic) or when using the AC (I think) they both will run at a higher speed.

Jaap

cooling fans - flash - 05-10-2009

what i read as "wrong" was where they came on - the low speed should come on just above the 8 o'clock line, not the upper line (10 o'clock) - the high speed fan should come on there

cooling fans - PorscheG96 - 05-10-2009

Same exact scenario w/ my 968. Both fans were turning on at the 10 o'clock white mark on my temp gauge and continued running until temp gauge indicated 8 o'clock white mark. Installed brand new temp switch yesterday PN 95160648100, properly bled cooling system, but still no low speed fan operation. Today I'm going to swap fan relays w/ Arash to see what happens, then begin checking the fan resistors.

cooling fans - PorscheG96 - 05-11-2009

Today I tried plugging in a fan relay from a 968 with fans that are working correctly but this didn't change the behavior of my cooling fans at all so I swapped my own fan relay back in. Next I turned on my air conditioning with the engine running and both fans operate the same way as when my temp gauge reads 10 o'clock. According to Clark's Garage, the fans operate at low speed with the air conditioning on, not high speed like I always thought. Arash had a wire to jump the fan switch connector in order to test low and high speed fan operation which we found quite interesting because both fans turn on at both high and low speed but they receive different current due to the fan resistors. If you listen closely to the fans then you can hear a resonance like waaah-wahhh-waaah, etc. Well this resonance occurs at about 0.5-1 hz at low fan speed and 3-4 hz at high fan speed which can be used to diagnose which speed your fans are operating at. Therefore it's never been the high speed fans that I was hearing with my temp gauge at 10 o'clock, but the low speed fans instead so at this point I think that the temp gauge is reading high and there's nothing wrong with the cooling system itself!

cooling fans - xrad - 05-13-2009

I'll bet it's a manufacturing error(or Porsche decided it was not necessary for dual speed temp sensor) and thousands of the wrong temp sensors are out there. Flash is right, there is a low speed fan and a high speed (AC) fan. Jumping the plug proves the dual circuit is fine. Only thing left is the rad temp sensor (and this was specifically purchased as a 968 rad temp sensor..not a substitute)

cooling fans - unknown4u - 03-16-2010

Today I checked the circuit for low and highspeed by jumpering the wires from the thermoswitch. Low and High circuit is good shape.
But I have the same symptoms after replacing the thermo switch 92/102 degrees.
Fan kicks in before the 10 O clock area and kicks out at almost 8 O clock.
As far as I can hear the fans are running on low speeds when they kick in.

Can somebody tell me what is wrong?

I would like to have a system that has a constant temperature and that is not fluctuating like this.
For your information: The gauges fluctuates since I owned the car. And I was considering the thermoswitch was shot at low speeds.

Anybody suggestions?

cooling fans - PorscheDude - 03-16-2010

Check your grounds. There are a few behind the cluster.

cooling fans - jlm968 - 03-16-2010

Might also be the relay, PN 944 615 104 03.

cooling fans - unknown4u - 03-16-2010

Why the grounds?

This because if I jumper the connector from the switch it works correct.
This for the low and high position.

The relay isn't an option either because by the same jumpermethod it works correct.

Can somebody explain this? Or is this the gremlin inside?

cooling fans - John - 03-16-2010

Go to the DIY Library/Electrical ... section, select the Electrical Trouble-shooting the Porsche 968 Cooling System topic, download the file you will find there, and run the diagnostic tests.

cooling fans - banditsc - 03-16-2010

Have you cleaned the connections on the resistor pucks on the firewall? They are on the passenger side inner firewall in the engine bay, they are behind the battery on a US car.

cooling fans - unknown4u - 03-16-2010

John I Did check all the test as described in the document.
But the needle of the gauge is almost at 10 o clock before stage 1 kicks in.
And stops just before the 8 o clock mark.

I als o heard from other members that there needle is always, no matter what circumstance, stuck at 8 o clock.
Am I write or wrong?

My coolingsystem is in good shape, and the test as described in the documents give no faults.

cooling fans - John - 03-16-2010

unknown4u, if the diag. tests checked out, then I'd look at the thermostat, the temp. sender (per Clark's Garage), the temp. gauge accuracy (again, per Clark's Garage) and the inst. cluster grounds (for the gauge), in that order.

I had a similar issue after replacing the thermostat during a fit of preventive maint., and spent a lot of time and energy trying to find the problem. Somewhere along the way I read that not all thermostats were created equal, and tested the thing. It was no good! Replacing it, with a newly tested one, solved the problem. Hope this helps.

cooling fans - unknown4u - 03-17-2010

Thank John for the information. After the replacing of the thermostat at your car is the tempgauge always stuck in the same position?
I'll have to check that thing too.
Is never replaced by me since I own the car.