Driver's side cooling fan Inop--FIXED!!!
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Racer
Joined: Jul 2009
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From: Byhalia, MS
The wiring is good from the amp to the fans. There is no physical damage to the harness on the driver's side. I've hooked an ohmeter using spade connectors on the plug eng and wiggled, pulled, slapped around the harness with the ohmeter connected with no fluctuations on the meter; solid continuity.
leadfoot, I've checked around and no one seems to have the BUZ11A MOSFET. Probably out of production now.
For now, I'll move on to my LH airbag sensor high resistance issue. Hopefully that one will be a bit easier to rectify. I'll continue my search for the mosfet. I'll eventually find one.
Thanks for all the input. This forum rocks!!
leadfoot, I've checked around and no one seems to have the BUZ11A MOSFET. Probably out of production now.
For now, I'll move on to my LH airbag sensor high resistance issue. Hopefully that one will be a bit easier to rectify. I'll continue my search for the mosfet. I'll eventually find one.
Thanks for all the input. This forum rocks!!
Chronic Tool Dropper
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The wiring is good from the amp to the fans. There is no physical damage to the harness on the driver's side. I've hooked an ohmeter using spade connectors on the plug eng and wiggled, pulled, slapped around the harness with the ohmeter connected with no fluctuations on the meter; solid continuity.
leadfoot, I've checked around and no one seems to have the BUZ11A MOSFET. Probably out of production now.
For now, I'll move on to my LH airbag sensor high resistance issue. Hopefully that one will be a bit easier to rectify. I'll continue my search for the mosfet. I'll eventually find one.
Thanks for all the input. This forum rocks!!
leadfoot, I've checked around and no one seems to have the BUZ11A MOSFET. Probably out of production now.
For now, I'll move on to my LH airbag sensor high resistance issue. Hopefully that one will be a bit easier to rectify. I'll continue my search for the mosfet. I'll eventually find one.
Thanks for all the input. This forum rocks!!
Chronic Tool Dropper
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The will run on cooldown if either the temp switch in the top of the intake is hot, or the ATF temp switch in the auto trans says too hot. I'm not sure how running the fans cools the trans when it isn't pumping, but there is a function for that anyway. When either of these switches is engaged, the fan runs at low speed.
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I chased an inop fan for months, as had the PO, who got around it by running a relay off the powertake-off in the engine bay. I did not like that so went back to basics to trouble shoot it. I took the fan controller apart and found some capacitors with corroded legs, fixed those and it still did not run. I replaced the mosfets and took aout and tested each transitor, resistor and diode. So many hours!
I got the controller to work but then shorted it when I put the back on. In the end I got a replacement but that did not fix the fan. To cut a long story short, it was the fuse holder which had lost its grip on the fuse. The fuse would not blow, but would get too hot due to poor connection and increased resistance. The fuse would sag out of the little copper jaws. I replaced those and its been working fine for 4 years now.
I got the controller to work but then shorted it when I put the back on. In the end I got a replacement but that did not fix the fan. To cut a long story short, it was the fuse holder which had lost its grip on the fuse. The fuse would not blow, but would get too hot due to poor connection and increased resistance. The fuse would sag out of the little copper jaws. I replaced those and its been working fine for 4 years now.
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Racer
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From: Byhalia, MS
Here's an update.
I swapped out the fan amplifier with known good. Same problem. Checked the power to the fan amp for fan1 and fan2. Power is good as I jumpered power at the fan amp plug straight to each fan and each fan works fine connected to power through its appropriate fuse. That eliminates the power to each fan, ground to each fan and the associated wiring.
ARGH, frustration is mounting.
Wierd thing: I can swap the signal pins at the controller and the only fan that runs is the driver's side fan. I believe its pins 6 and 8 that are the signal pins.
Any ideas? This one is starting to get to me
I swapped out the fan amplifier with known good. Same problem. Checked the power to the fan amp for fan1 and fan2. Power is good as I jumpered power at the fan amp plug straight to each fan and each fan works fine connected to power through its appropriate fuse. That eliminates the power to each fan, ground to each fan and the associated wiring.
ARGH, frustration is mounting.
Wierd thing: I can swap the signal pins at the controller and the only fan that runs is the driver's side fan. I believe its pins 6 and 8 that are the signal pins.
Any ideas? This one is starting to get to me
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I have also a non working fan on drivers side.
Read all through this post and I feel like leaving it alone (but I don't).
I think first thing to do for me is to examine the MOSFET issue.
My fusebox looks OK so a loose connection would be not the first thing I would look for.
Somebody told me that Porsche could program the whole system differently for different regions.
Are we 100% sure the two fans sould ALWAYS operate at same time or does the 2nd kick in at higher temps on cars with alternative program ?????
Thanks,
Paul
Read all through this post and I feel like leaving it alone (but I don't).
I think first thing to do for me is to examine the MOSFET issue.
My fusebox looks OK so a loose connection would be not the first thing I would look for.
Somebody told me that Porsche could program the whole system differently for different regions.
Are we 100% sure the two fans sould ALWAYS operate at same time or does the 2nd kick in at higher temps on cars with alternative program ?????
Thanks,
Paul
Thread Starter
Racer
Joined: Jul 2009
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From: Byhalia, MS
Everything I read on the subject states that the 2 fans should run at the same times... I had a fluke the other day after I moved the wire harness a bit. The driver's fan worked for about 2 hours. Then back to the same old problem. I'm sure its a wire. I'm thinking it the signal line from the controller to the fan amplifier. I'm going to work on it this weekend and will update with any results.
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Racer
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From: Byhalia, MS
5 & 8 are the power outputs to the fan motors. They are controlled by 7 & 6, the pulse width modulated signals from the controller next to the passenger seat. 1 & 4 are the 12 volt supplies from the power fuses to each fan.
Last edited by DanielD; May 29, 2010 at 12:56 AM. Reason: Clarification
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