jack.pe

Just got my 964...There is already a small issue though. one of the bower motors does not go off, even when the car is parked with keys out. Most of the air that comes out does so from the bottom vents. By removing the fuse it stops but then no heating.. I tried removing the relay marked 1 in the pic (R04) which is supposed to be the blower relay according to the diagram but it still goes, even with that relay removed from the board. Also oddly, next to it (R14) according to the diagram there should be another blower relay but there is nothing there? any ideas? I'm a bit annoyed this did not come up in the inspection.

jack.pe

Ok, isolated it to the front blower. This is the one that does not stop...

Taking the fuse out makes it stop. As mentioned it is the missing relay which bothers me.. R14. Would the motor work without the relay and just stay on permanently?

ToreB

You probably have a faulty high-current driver (blower final stage) for the front blower motors. A short-circuit in the internal transistors will make the fan(s) run even with ignition off.
The final stage is tucked in behind the fuse box in the trunk, under the plastic cover for the HVAC servos.
Search for final stage to get any other details.
Cheers,
Tore

boxsey911

R04 is the relay for the oil cooler blower that is located in the front right wing just behind the wheel arch liner.

R14 is the relay for the air con condensor blower that is located in the front left wing. If you don't have aircon then you won't have that relay.

The cabin blowers (left and right) do not have a relay in the fuse box. You can stop them by pulling fuse 1....which it sounds like you have done. Or by unplugging the final stage amplifier which I mentioned in your other thread.

Here's one on ebay so that you can see what Tore and myself mean:

http://www.ebay.co.uk/itm/PORSCHE-96...item256f46b0e5

jack.pe

Steve, Tore,

Thanks for this, much appreciated. just a had a look and found the final stage. When unplugged the motor stopped, does this mean it is definitely faulty? if so ill get the part on Ebay!!

ToreB

Most probably yes.
It would be possible to do another test with a oscilloscope to determine if the CCU sends the correct signal to the Final stage. But, this could be a difficult task due to the need for also spoofing a correct feedback signal from the fan motor.
I would go for a new final stage amp first, especially with the above price.
Cheers,
Tore

jack.pe

Thanks Guys!!!

Have bought the ebay part and will let you know!

boxsey911

Fingers crossed for you Jack. When it arrives, just plug it in without removing the old one to check it fixes the fault. If it does, then remove the old one being careful to not drop the two bolts that fix it to the wall.

jack.pe

Received the final stage today and will try when I get home. Fingers crossed. On another forum someone has suggested the ECU was the culprit for them. Hope this is not the case for me. Sounds expensive.

ToreB

The Climate Control Unit is fairly simple to repair, don't worry.
Have a look here: www.porschehvac.bergvill.com
Cheers,
Tore

jack.pe

Tore and Boxsey,

It was the final stage!!!! All good now. Thanks so much guys really appreciate it and so lucky there was a second hand part on ebay..

Kahdmus

Glad you got it sorted.

My climate-control servos seem to get stuck at least once every 12 months or so. Each time I open them up, bend the conectors back so they are making good contact and liberally clean with WD40. So far has done the trick every time, however, replacing those darn rear nuts without dropping them into the unknown, always seems to take longer then the rest of the entire procedure!

ToreB

Great news.
Cheers,
Tore

boxsey911

Good news Jack

jotaking

Hi Everyone

Total newbie and just purchased my first 964. I have a similar issue to the one described above. The blower is always on in the cabin. Mainly blowing warm air into the footwell. It does shut down when I turn the ignition off.
I have ac and the ac doesn't work as no cold air comes through. All controls on CCU seem to work okay, other than AC button has no effect to temp and one time when I turned the dial to 4 and the fans came on full, when I dialled down they stayed on full? When I turned the ignition off the fans stopped and when I restarted next day the system worked again (other than cold air). I believe the AC gas is still he band type, not sure of the number R***. This leads me to believe that the ac hasn't been looked at for some time.
I was hoping that a gas re-charge may solve my problem??
Am I that lucky??
Any advice welcome....Thanks in advance
Steve