Only left radiator fan comes on. Problem? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

professorman · 06-15-2016, 06:47 PM

I was running my car yesterday for a while, and I noticed that I can only hear my left radiator fan come on. I turn on the A/C and the right fan still did not come on. How can I trouble shoot this?

I have a 01 Boxster base 5spd w/94k miles.

BoxsterSteve · 06-16-2016, 12:15 AM

Pull the offender and put 12v to it directly. If it still won't run, it's a goner.
If it runs when powered directly, the relay that switches it and/or the ballast resistor would be your next parts to investigate.

mikesz · 06-16-2016, 11:43 AM

FYI resolve it quickly. My left fan wasn't working and was binding causing row in the fuse box to fry.

professorman · 06-16-2016, 11:45 AM

Quote:

Originally Posted by mikesz

FYI resolve it quickly. My left fan wasn't working and was binding causing row in the fuse box to fry.

Wow..... Thanks for the tip.

thstone · 06-16-2016, 04:35 PM

Most likely cause is the ballast resistor. Very common failure. Do a search, lots of posts on troubleshooting and repair. I've done two of these - one on my earlier Boxster and one on the 996.

Fuzzuki · 06-16-2016, 05:42 PM

I have a 2000 Boxster.
Today in 28 degree temperatures in traffic she got pretty hot.

I had to pull over to cool her down.
I hear a fan in the engine bay behind me.
What does it do? How does it cool the motor when the rad is out front???

There are fans on the front rads????????

How do I check them?

thom4782 · 06-16-2016, 06:47 PM

To test...turn on car, then turn on a/c. Fans always run then at low speed,

If one fan doesn't run, then its either the ballast resistor, the fan motor or the fan relay. You can test the relay by swapping it with the relay from the working side.

paulofto · 06-17-2016, 07:02 AM

Quote:

Originally Posted by Fuzzuki

I have a 2000 Boxster.
Today in 28 degree temperatures in traffic she got pretty hot.

I had to pull over to cool her down.
I hear a fan in the engine bay behind me.
What does it do? How does it cool the motor when the rad is out front???

There are fans on the front rads????????

How do I check them?

The fan in the engine bay is to move air surrounding the engine. Air is drawn from below and pushed out the passenger side vent. There are 2 fans out front, one for each radiator. The S model has a central rad as well but no fan behind it. Follow Thom4782 advise to test the front fans

mikesz · 06-17-2016, 10:03 AM

there is also a good DIY somewhere I think on Pedros board on how to make a jumper and removing the 4 relays for the 2 fans and "jumping" the bottom slot with the top slot for each fan relay. that is how I diagnosed my issue.

san rensho · 06-17-2016, 11:21 AM

If its just the ballast go to parts geek and get the radiator fan /ballast combo for about $160. The ballast is about $110 and in the future you will need to replace a fan.
I had to replace both fans on mine.

Fuzzuki · 06-17-2016, 11:42 AM

Quote:

Originally Posted by san rensho

If its just the ballast go to parts geek and get the radiator fan /ballast combo for about $160. The ballast is about $110 and in the future you will need to replace a fan.
I had to replace both fans on mine.

Where did you get this deal?

Where are the balist resistor's?

Parts geek. Com?

Fuzzuki · 06-17-2016, 11:43 AM

Forgot to mention. Drivers side fan runs and not the other when the AC is turned on

thom4782 · 06-17-2016, 12:45 PM

Quote:

Originally Posted by Fuzzuki

Forgot to mention. Drivers side fan runs and not the other when the AC is turned on

Still the same issue: broken fan motor, ballast resistor, or relay or its a break in the wiring.

If you switch the relays the passenger fan still doesn't run, then think fan motor or resistor.

If the weather is hot and you let the car run at idle until the fan switches to high speed as the water temperature rises and the passenger fan still doesn't work, then the fan is the problem.

If the passenger' side fan comes on at high speed, then it's the ballast resistor

If you have a Durametric cable or know someone who has one, you can test the fans in low and high speed modes without having run the car.

Fuzzuki · 06-17-2016, 03:49 PM

Quote:

Originally Posted by thom4782

Still the same issue: broken fan motor, ballast resistor, or relay or its a break in the wiring.

If you switch the relays the passenger fan still doesn't run, then think fan motor or resistor.

If the weather is hot and you let the car run at idle until the fan switches to high speed as the water temperature rises and the passenger fan still doesn't work, then the fan is the problem.

If the passenger' side fan comes on at high speed, then it's the ballast resistor

If you have a Durametric cable or know someone who has one, you can test the fans in low and high speed modes without having run the car.

Thank you. Very much appreciate your response.

My wife I'd going to kill me. Having to work on my car all the time.
I used to work on my old motorcycle's until she grew tired of it and make me buy a new bike.

Maybe I can get a new Boxster if this continues.

LOL

Pdwight · 06-17-2016, 08:27 PM

I have been working on and repairing things all my life (turn 60 in a few days), you say you got the fan motor going ?

Unless you found something wrapped around the motor binding it it is probably toast. I have gotten many motors that were seized going...penetrating oil etc. I have found if a motor ever seizes it's life is most likely over, you might get it going for a while but it will fail on you again. Summer is not a good time for a cooling motor to go out, get a used one from Woody if there is any drag whatsoever in that motor. It might cost a little right now but seem like loose change compared to an engine later.

san rensho · 06-18-2016, 10:12 AM

lQUOTE=Fuzzuki;499871]Where did you get this deal?

Where are the balist resistor's?

Parts geek. Com?[/QUOTE]

01 2001 Porsche Boxster Radiator Fan Assembly - Cooling System - Bosch - PartsGeek
01 2001 Porsche Boxster Auxiliary Fan Resistor - Cooling System - Genuine - PartsGeek

Fuzzuki · 07-02-2016, 06:16 AM

Here is the update. I was away in Switzerland. At home, my wife and child were driving around and heard a weird noise. Very weird. Never heard a car make this kind of noise.
I checked around, saw that the power steering reservoir was empty. filled it up and still heard the noise. I was thinking the power steering pump was finished.
Brought it to Mantis Racing in Oakville.
The found it was the water pump. They replaced it and found that neither fan was kicking in.

They replaced both resistors packs and now all is well.

My Visa would say otherwise. But, so be it.