milutintin

Hi everybody,

I have removed and unmounted the small fan behind the CCU because it doesnt work as it should. Sometimes it works and sometimes it requires some hand force to start rotating.

In my opinion the motor is a brushless dc motor with two magnets in the rotor and one electromagnet in the stator.

When both magnets are in the horizontal position the fan works. If they are in the vertical position the fan doesnt work. If you move the rotor until horizontal position then the fan starts working again.

Any help fixing it?

I've also thought of replacing the inside fan with a 12v computer fan.... Does it sound very crazy? What should be the amperage of the computer fan?

Thanks

Dsqr964

The amperage of a muffin fan (PC Internal Fan) is low, very low. Check the amperage of the size of fan you are going to try to use. The thing is also if you could find the CFM (Air Flow the fan can create) rating of the CCU fan and try to match it with a muffin fan. Another thing will be to direct the air flow into the CCU so you may have a bit of fab work as well.
I have priced the fan unit, a bit pricey for the thing IMO. The magnet issue is interesting, I would have to play around with it to find the root cause is. Good luck Sir and post pics of your fab work if you go that route. -D²

vracer

OK, I'll bite. What's the ccu, and how do you know if the fan is working?

John Boggiano

Climate control unit. Stick your finger around its back, right-hand corner and you can feel the little fan.

Laker

CCU = Climate control unit, It is the box in the dashboard that has the temp controls and sliders. It slides out like a Radio. Inside is a little fan that sucks in air from the cabin, so it knows what the current temp is.
If you turn on the igntion (don't need to start) for approx 30 seconds IIRC, and turn it off, you should hear a fan running inside the dash for several minutes.

I cleaned off gunk from the spindle, put in a drop of TriFlow and re-assembled and heard it after the ignition was switched off for the first time. Easy fix

vracer

Laker, you always come through, thank you, and thank your John.
Richard

milutintin

I have bought this fan SUNON KDE1204PFV2

http://www.frozencpu.com/fan-23.html

According to the manufacturer the specifications are:

12v dc
0,08 amp
1 W
5800 rpm
7.0 CFM (Airflow)
0,13 inch-H20 (Static pressure)
27dB

Now I am planning on how to replace the original fan with this one using the same case.

Do you see anything wrong? I'm concerned about the fan wires. The originals are thicker than the ones in the new fan...

Dsqr964

If you can mod the enclosure to accept the fan then you should be ok. The size of the wire could be due to the fact the original CCU fan draws more current than the muffin fan. -D²

Laker

milutintin, try my suggestion, wipe a cloth up and down the spindle and try a drop of a very light teflon oil (like Tri-Flow) It may just start working again.....

milutintin

Laker: Thanks but I already tried that and it didnt work.

milutintin

Already replaced the fan outside the car. Still pending on reinstalling the CCU in the car.

Some notes:

- It's noisier than the original fan.
- This fan is an axial fan and the original was a centrifugal fan (http://en.wikipedia.org/wiki/Centrifugal_fan).
- The air flow is parallel to the axis in the axis fan and is orthogonal in the centrifugal fan.
- It could be that the new fan is not getting the same air flow as the original one. Apparently it does.

Any notes?

milutintin

Already installed in the car. Apparently it's working properly. I think it's noisier than the original but I am not completely sure as the fan wasn't working before.

Dsqr964

Awesome work, now I know if mine goes out I can just replace it with a muffin fan, very cool! Thank you Sir for sharing. -D²

ToSi

Bump,

Dismantled my CCU to clean 15yrs worth of dust / grit (have a '96 993) & to try fixing a non-functioning max AC switch. In the process of testing the bulbs & fan, noticed the same phenomena - when supplied ~13.8v from a desktop power supply, the fan sometimes starts fine & sometimes needs a nudge. How can this happen? Weakening of magnets over time?

Once spinning, it is silent & smooth. Fan OK or needs replacing?

Assuming the fan controller magic is still working, otherwise it wouldn't keep spinning.. Any EE's in the room who can shed some light on this?

GazC2

This is an excellent site, and tore is very helpfull

http://privat.bluezone.no/toreb2000/ccurepair.html