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YOUR RESEARCHsome clarification on the radiator fans...
Reported or suspected cause
most likely the coolant temp switch
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Your problem is most likely the coolant temp switch.
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Suggestion
there is a way to check by "jumping" the high speed and that tells you if the fan is OK...resistor can be replaced but it is a "solder in" part at about $100 IIRC
Leading evidence: 'most likely the coolant temp switch' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'most likely the coolant temp switch' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check by "jumping" the high speed' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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I ran into the same problem a 2 weeks ago when the weather here in Toronto started hitting the 90's.
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I simply used 2 toggle switches that I installed in the batwing,
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Suspected cause
Your problem is most likely the coolant temp switch.
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Check by "jumping" the high speed
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Suggestion
there is a way to check by "jumping" the high speed and that tells you if the fan is OK...resistor can be replaced but it is a "solder in" part at about $100 IIRC
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
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Update: I jumped the working fan and it worked in high, the non-working fan is free to move...
I was messing with my car the other day and i realized only one radiator fan was coming on. I read that they are staged (hi and low setting?) Just to clarify.. they both should be coming on at the same time and depending on the coolant temperature they should switch from low to hi speeds, am i understanding this correctly?
If this is true then i need to do some troubleshooting on that driver's side fan.
Also, will both come on when the A/C is switch on?
As I understand they both should be running with the AC on at low speed. When the temperature rises above a certain point the both will switch to hi speed.
I get this one -
ready....
Resistor!!!
so the voltage sent to the radiator for "low" is sent thru a resistor, it fails. there is a way to check by "jumping" the high speed and that tells you if the fan is OK...resistor can be replaced but it is a "solder in" part at about $100 IIRC
I will post a link
LINKY LINKY
no need to pull parts,... you can access the ballast resistor from the wheel well (remove liner) and access the relay box on your back near the pedals... after "jumping" mine I left them jusmped so my fans always worked on high... knocked the heat out of it faster on hot days.....
Ed,
How come you know so much about radiator fans? Your car doesn't even have a radiator. Or did you install one on your car since it was "left over" radiator from a GT2?
was the other fan running?? I have not read that for a while so I am not sure if that jumper only works to turn on "high" when "low" is ppowered or if it is a "full time on" jumper...
try running the car till the low fan on the other side comes on and/or use the A/C and check again... it is possible the fan went out, but unlikely IMO.... this test will tell you for sure if the fan is dead though...
and yes Tim, I have a third radiator but not the first and second
just kidding
Try and rotate the dead fan and make sure nothing is blocking it from moving, if good, jump the working fan and see if it runs on high, if good redo the dead one, if still dead remove fan and bench test.
This is from memory, not manual
Electronic Gurus:
I just measured the voltage from pin 87 to 30 and it was 11.1 volts on the low left fan (not working)
then i measured the voltage on the right side and it was 12.6 volts (working fan).
could the fact the voltage is less on the fan that isnt working be a factor. Also, the volts from pin 85 to 86 was 8.6 on both relays..
Ideas?
Well $hit, I got ya as far as I am able to.
At this point I suspect the fan. Before I bought one I would swap sides with the good one and see if it worked.
Then go buy a new/good used fan
Sorry man, over my head if its more than that
hey i got the fan off, now one question, what is that cylinder that is located on the bottom side of the fan? i ensured that 12v whats making it to the harness for the fan, so im now tearing the fan apart to see if i can fix something internally. the fan is definitely the problem unless its this funny tube/cylinder attached to it..
UPDATE: BOOYAH.... i fixed it.. the brushes on the fan motor were seized and were not touching the inner race. ( i moved the brushes in and out with my finger and they are all better) Its similar to a starter if you have ever taken one apart.... hopefully this post maybe helps someone out with a fan problem
Do the fan mod.... really comes in handy in avoiding high temp.....
Radiator Fans
Connect a wire to the ground (Pin #85) of the 2 high speed fan relays located on the relay carrier located in the driver�s side foot well. The relays are #20 and #22. Feed this wire to where your switch will be located. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and then connect the other end of this wire to a chassis ground point.
With key on, this switch will now immediately turn on both radiator fans providing maximum cooling. When you turn the key off, the fans will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off.
Engine Compartment Fan
Connect a wire to the ground of the relay located in the relay carrier behind the passenger seat, driver�s side. Relay #8. . Feed this wire to where your switch will be located. I simply fed the wire along the driver�s side of the car and under the door sill. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and connect the other end of this wire to a chassis ground point.
With key on, this switch will now immediately turn on the fan drawing air into the engine compartment. When you turn the key off, the fan will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off. This mod helps keep the engine compartment much cooler when driving around town and is particularly beneficial to any engine that draws its intake air from inside the engine compartment, such as the EVO SC.
If you are adventurous, you can automate the operation of these switches so they will switch off at a specific speed, or operate when vacuum is present only, etc. You can choose any style switch you want and even use Porsche switches (relay required). I simply used 2 toggle switches that I installed in the batwing,
ride, you missed my comment that I ran mine on high and by-passed the resistor using just what I showed you on that link... I didnt want a switch and since they come on at low speed automatically, i just kept the jumpers in so they came on at high...
search "fan mod" I am sure soomeone took pics
PS - yea, that manual isnt much
gotcha, i didnt realize that the mod actually allowed the fans to kick on "high" during "low" setting. Now, do the fans get the coolant temp from the coolant temp sensor? (which then determins high or low fan settings?) I'm trying to wrap my head around the whole purpose of the resistor...
And know all of you are talking about a Boxster. I have a 996 Porsche 2001. Maybe some of you can help me with this question. Both of my fans will turn on only if the AC is on. With the AC off no matter what the temperature is the fans will not go on. I don't know if this is a relay problem or a resistor problem. Maybe someone can shed some light, because the air conditioner has to be on all the time. Maybe this is not too bad during the summer months, but it's not the way it should be.
I would appreciate your comments
thanks Vince
grp5 - what temp are you saying when you say "no matter what the temp is"
there is a diagnostic tool built into your HVAC controls, have you accessed it and looked at the actual reading? (or just the guage)
check fuses first
then by-pass ballasts
then bench test fans (or use ohm meter and watch for power to come thru at the relay when signal leave DME
I'm a newbie to Rennlist, and I don't even own a Pcar (yet), so take my input with a grain of salt. If it were me, I would rule out the relays by pulling the left relay (known good) and installing it in the right relay socket.
If you get no joy from that. I might get some junk speaker wire and unplug the right fan connector and "hot wire it" directly to the battery. Not for long, but just to see if the fan motor is kaput (that's a German word, right?). If it turns you can rule that out as a culprit and keep using the process of elimination to rule out things you can easily test.
Wish I could be more help, it's not like this is my first automotive rodeo.
Mel
Thanks for the idea Mel
the OP fixed his problem, but that is worthy of noting and might help someone down the road!
SOOOOO - lets hear the story as to why no car (yet)
Currently, I'm here educating myself, so I know how to buy a 996, which is my current model of lusting.
To prevent the dreaded duplicate post,
here is a link to that story.
Refer to post 100 of the same thread for the "originating post".
I've got roughly a year left, before a lot of allocated cash get's freed up. After some major renovations on the house and finding and buying her an AMG Benz, the wife is a little more pliable about what I want and a 996 is clearly a toy for me.
If I could turn the clock forward, I'd like to consider
Ahmet's car
that looks very nice to me.
Mel
Hey thanks, I like my car quite a bit too. We'll see what's in store for me...
On to the fans, I know this has been clarified some but both fans should always work together. They should both be off, both on low or both on high speed. If one fan refuses to work at all, it's likely the fan itself may be at fault, as in this case, or it could be the resistor. The resistor also seems to often cause no low speed operation. I've yet to see a failed relay or blown fuse, but of course it's very easy to check those so a prudent place to start...
Fan operation is (supposed to be) as follows:
A/C off, fans are off when coolant is cold, at X temp they switch on low, and at Y temp they switch on high.
A/C on, fans are on low speed, at temp X they switch to high speed, they continue at high speed through coolant temp Y.
Also from experience tracking a C2 without a center radiator (my previous car sold to another board member), removing one fan improves cooling at speed/on track. I've heard from several factory and race prep. techs that cutting the inner fender liner also helps at speed, and I'd be inclined to agree, similar to the factory GT3 or 997 MKII cars, but I have not tried either of those personally since my current car sees more street work where cold A/C and lower coolant temps in stop/go is preferable.
ivangene-" when they say no matter what the temperature is"
if the ac is not on, the fans will not come on. Therefore the car will overheat and the engine light will come on. There is nothing wrong with both fans. So I have to turn on the AC and eventually the engine will cool down, and the engine light will go out.
That is hot!
But the fans both work, so it is mot relay/fuse. Must be a sensor.
Someone else might know about that. Post findings and a pic and for goodness sake don't overheat it!
You should not run the engine that hot, ever. Could rather easily blow a headgasket or crack a cylinder head, etc. If this were a BMW straight 6, your engine would already be toast!
Your problem is most likely the coolant temp switch. If your fans never come on at high speed, this would be another data point that would point to the switch.
To ride123:
I ran into the same problem a 2 weeks ago when the weather here in Toronto started hitting the 90's. Same problem of the driver side fan not coming on at all. Thanks to your post, I found the exact same problem with the brushes in the fan motor being stuck. Cleaned them out, now smooth as butter and my fan's blowing up a storm.
Thanks for sharing your experience as well as the resolution. Ain't this board great?
Add one to the "free repairs" group!
