Re: Running with Low speed fans not working??

From what i have researched regarding the front fans.The low speed comes on at 206 degrees and the high speed comes on at 216 degrees.Both my high speeds work but
both low speed do not.Fuses are good.Would it be ok to just run the car with high speed working only.For 10 degrees is seems like its really not necessary.
Porsche wants close to $300 cdn per Controller or Ballast resistor. Is there a down side to not fixing this.Thx

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moresquirt
From what i have researched regarding the front fans.The low speed comes on at 206 degrees and the high speed comes on at 216 degrees.Both my high speeds work but
both low speed do not.Fuses are good.Would it be ok to just run the car with high speed working only.For 10 degrees is seems like its really not necessary.
Porsche wants close to $300 cdn per Controller or Ballast resistor. Is there a down side to not fixing this.Thx

My info is the fans come on low speed at 212F and switch to high speed at 216F. But different model years might be different.

I would not continue to use the car any more other than to drive it to a place to have this addressed so the fans work properly come on low speed when they should at the low trigger temperature and switch to high speed at the high trigger temperature.

I have had one fan quit on both the Boxster and the Turbo -- the Turbo's fan motor shaft snapped -- and never noticed a cooling problem but I treat the two radiator fans as backups to each other. One can quit but there is a 2nd one and as long as this is working I feel comfortable at least driving the car to a place to have the fan problem addressed.

With both fans not working even at low speed that a bit too far over my comfort line and I would not could not continue to drive the car normally. My driving would consist of getting the car ini and having this addressed.

Thx for the feedback Marc.Pedro .could u chime in here with your thoughts.I called a local Porsche shop (not dealer) .They advised me that it may only be a problem if
i get into heavy traffic when its really hot out but here in the country were i live and spend most off my time in the car it would be rare to be in heavy traffic.Take that for what its worth..I am still trying to find an after market unit.I have read lots on the subject and many have installed aftermarket Resistors that have worked well but i believe they were working on a different model.

Why are you looking for an aftermarket ballast resistor?
The OEM is not very expensive.
Installing it is a different story because it has to be soldered in and its location is uncomfortable to work in.
It takes about 90 minutes to replace one.
In a hot climate I would not recommend driving around with the ballast damaged although if you run the A/C the the fans run at high speed.
Happy
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

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I guess i am not totally sure its the ballasts.I did check all the fuses and there all good BUT if i hold my fingers on all the Relays and turn the air conditioner on and off i do not
feel or hear any click.I pulled 2 Relays and reversed them but no change,Mine on my 987.1 are different than the 986 layout.Is it possible its the Relays.I need to figure out
what ones are low and what 2 are high speed.There are actually 5 Relays in total.What would the 5th be for?

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moresquirt
I guess i am not totally sure its the ballasts.I did check all the fuses and there all good BUT if i hold my fingers on all the Relays and turn the air conditioner on and off i do not
feel or hear any click.I pulled 2 Relays and reversed them but no change,Mine on my 987.1 are different than the 986 layout.Is it possible its the Relays.I need to figure out
what ones are low and what 2 are high speed.There are actually 5 Relays in total.What would the 5th be for?

WAG would be for the engine compartment fan.

A tech would use bypass/test relays to confirm the relays were good.

He would then probably disconnect each fan from the wiring harness and use a test harness connector connect shop 12V power directly the fan connector to determine if the fan worked with as little between it and the power source as possible.

Hi Marc,thx for feed back.What i have learned so far.The 987 is a totally different animal than the 986.Those Relays have nothing to do with the fans.The 987 has a Controller attached near the
fan on the passenger side.Basically a mini computer.It has the Relays built into it.Its not a Ballast Resistor like the 986.Its approx $300 cdn for the controller.No one sells a after market unit.
What i have not figured out yet,(if someone can comment) is if the fans assemblys have a low and high speed motor or if the controller activates the speed.I am leaning toward the fan having 2 motors.
So this problem could be a few things,the low speed motors on both,the Controller,corosion in the wireing connection from the controller to the fan.I am looking at again today now that i understand
more and check power all the way thru the system.There is also 80 AMP Fuse in the front trunk,passenger side for the Fan but if the high speed both work then i am ruling that out.Keep u posted.
If i havent figured it out by monday then i am taking it in.

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moresquirt
Hi Marc,thx for feed back.What i have learned so far.The 987 is a totally different animal than the 986.Those Relays have nothing to do with the fans.The 987 has a Controller attached near the
fan on the passenger side.Basically a mini computer.It has the Relays built into it.Its not a Ballast Resistor like the 986.Its approx $300 cdn for the controller.No one sells a after market unit.
What i have not figured out yet,(if someone can comment) is if the fans assemblys have a low and high speed motor or if the controller activates the speed.I am leaning toward the fan having 2 motors.
So this problem could be a few things,the low speed motors on both,the Controller,corosion in the wireing connection from the controller to the fan.I am looking at again today now that i understand
more and check power all the way thru the system.There is also 80 AMP Fuse in the front trunk,passenger side for the Fan but if the high speed both work then i am ruling that out.Keep u posted.
If i havent figured it out by monday then i am taking it in.

It does indeed read like the 987 is not like the 986 in the radiator fan department. To point out the obvious with both fans not working this strongly suggests a common failure so your investigation can start at the fans but you probably won't find the cause until you reach a point that a failure can affect both sides.

I suspect the two speed motor has one set of windings and is wound for one speed (for AC induction motors operating at 60hz the constant 7200 divided by the number of poles equals RPMs) but can be electrically reconnected to double the number of magnetic poles in the stator and the motor speed is reduced by half of the original speed which is also referred to as low speed. This is probably done in such a way that a failure of this undoes the electrical reconnection that doubled the number of magnetic poles so the number of magnetic poles is halved and the motor thus runs at full speed, also referred to as high speed.

This also highlights a concern arising from continuing to drive with the fans running at full/high speed. This subjects the fans to more wear and tear and can shorten their life. 'course, my 2002 Boxster's fans have run at high speed probably longer than most Boxster fans have run at low speed and my Boxster's fans are still going strong so maybe this is not that big of a concern.

If you don't mind be sure to report back what you learn. Given the 987 differs from the 986 in this regard I'd like to know what's going on.

UPDATE: I ended up taking the car in.They were able to get the fans to run on high and low.They hooked up the DME to a computer.Everything appears to work correctly BUT
the strange thing is the low speed fans will still not operate if car is cold and i start it up and turn on the A/C .Nothing happens until the temp is high enough then the low speed will operate.
It did it before last season every time i checked. They are not sure why its not working that way now .FYI they tell me that the 987 have never had issues with the low/high speed Controllers which
are feed info from DME in there shop and they see thousands of boxsters 911 and Caymens they now all come with this new set-up.That seems to be an issue from the past (986 Ballast Resistors)
on 986 (2004 and older) including 911,s.

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moresquirt
UPDATE: I ended up taking the car in.They were able to get the fans to run on high and low.They hooked up the DME to a computer.Everything appears to work correctly BUT
the strange thing is the low speed fans will still not operate if car is cold and i start it up and turn on the A/C .Nothing happens until the temp is high enough then the low speed will operate.
It did it before last season every time i checked. They are not sure why its not working that way now .FYI they tell me that the 987 have never had issues with the low/high speed Controllers which
are feed info from DME in there shop and they see thousands of boxsters 911 and Caymens they now all come with this new set-up.That seems to be an issue from the past (986 Ballast Resistors)
on 986 (2004 and older) including 911,s.

Since I'm woefully uninformed about the behavior of the 987 in this area I can't explain why there has apparently been a change in behavior. If the fans came on previously when the engine was cold and the A/C switched on why they no longer do this now seems to be to suggest a problem.

About the only thing I can think of is possibly a DME update/upgrade was applied and one of the differences is the fans are no longer turned on if the engine is cold even if the A/C is on. Perhaps this to reduce fuel consumption and reduce emissions at cold start by reducing -- if even slightly -- the parasitic loss the fans running represents?

I was at the dealer earlier today but had too many things on my mind to remember to run this by one of the techs. Next week when I pick up my car I'll try to remember and ask the techs what's going on.

until everything was warm for emissions reasons? The idea being to get everything in the cooling system to a steady warm state before you turn on the fans so you don't run rich as long.

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mikefocke, '01S Sanford, NC
until everything was warm for emissions reasons? The idea being to get everything in the cooling system to a steady warm state before you turn on the fans so you don't run rich as long.

Makes no difference. Because of the T-Stat no coolant is circulating through the radiators so the fans running has no effect on engine warm up time. However, when the A/C is on refrigerant is circulating and it has been compressed and is hot and the fans remove this heat to then turn the refrigerant back into liquid so it can at the right point in the A/C circuit be allowed to become vapor again.

The T-Stat will ensure the amount of coolant circulated will be restricted until all of the coolant is hot so everything gets to a steady warm state. With a real temperature gage one can see this as the engine idles and warms up the T-Stat will open a tad. In just a half a moment or two the temperature will drop again though as cool coolant begins to flow through the hoses/radiator and back to the engine. Because this coolant is cold the T-Stat reacts and closes again and then with more idle time subsequently opens again and the cycle repeats. However, the subsequent cycles are not that distinct as the temperature gage is not that sensitive of an instrument.

Another point: The condenser is ahead of the radiator so the air that is pulled in by the fan that passes through the condenser is warmed by this and then it will give up some of that heat to the radiator thus helping -- in some way, albeit some small way -- expedite the warm up of the coolant.

Interesting info Marc.I dont go to dealers but if u do and can discuss with a Tech that would be great.I tried calling a Porsch dealer
but got no were.They just say bring it in if u suspect a problem.They won,t let u talk to a Tech.