No defrost vent on 993

[hodol88]

I realize that I need to fix my windshield defrost vent if I want to continue driving my 993 through the winter.

There is no air coming out of the defrost vent. Thus, I can't defrost my windshield. Only air comes from the front dash even with the defrost button pressed, and there is a hissing sound. Where do I start?

[ToreB]

Maybe a stuck mixer servo or two?
See here for details: Porsche 964 / 993 CCU electrical repair
Cheers,
Tore

[porsche964guy]

The motor in the servo probably has gone bad. They are in the front compartment in front of the dash. Warn you they are very expensive and hard to get at. Their are 4 different servos. I have two of them left. Sold 2 already Not sure which ones I have, but if you are interested I'll check.

[ToreB]

The servos are available from Porsche, but at a high price.
PARTisan Autoteile in Neuried, Germany have a refurbish service at a lower price and with better quality than the new ones. I recommend them.
Cheers,
Tore

[hodol88]

Originally Posted by ToreB

The servos are available from Porsche, but at a high price.
PARTisan Autoteile in Neuried, Germany have a refurbish service at a lower price and with better quality than the new ones. I recommend them.
Cheers,
Tore

You have used PARTisan Autoteile? How much should I expect? Their website is in German. Do I communicate via email?

Thanks,

[ToreB]

I have had a lot of servos done at PARTisan, send Michael an email, there's a contact form on the web site.
Cheers,
Tore

[porsche964guy]

The two I have are:
964 624 903 00 Footwell flap
964 624 324 00 temp. mixing flap

I sold the other two:

964 624 901 00 fresh air flap
964 624 902 00 Defrost flap

I just noticed if you remove the tube looking yellow attachment from "964 624 324 00 (pic on right) temp. mixing flap" it matches the photos on Ebay being sold as "964 624 902 00" Defrost flap with the same number markings.

I'm told the Bosch Hammer can detect which servos and motors are bad.
If your interested in these I have let me know.

They have been tested by an Electrical Engineer and found good condition.

BTW I have the suitcase with all the levers and flaps if you need something.

[hodol88]

Thank you so much for your input. Does anyone knows how to manually set up the the mixer flap in open position for the time being?

[ToreB]

You could detach the servo connector and apply 12V to the motor pins (4 and 5) to move the arm. If not possible, you could simply detach the flap connection rod from the ball link and fix it with a nylon strip or something.
Cheers,
Tore

[porsche964guy]

I don't think you are going to want to do this twice. Its not easy getting at the flaps either. Notice the picture I attached. The metal firewall and gas tank are removed. Better to be ready with the parts you need and do it once unless you don't ever replace the motor servo and have continuous defrost.
If it was me and don't need the car for a while. I would remove the items in the way and get your hands on the servos to see if they are really bad or just jammed up. Then make my decision to get a replacement and change it to get it working or not.

[ToreB]

All the servos are easily accessible from the top, and only the plastic cover needs to be removed in order to change the servos. I normally spend about 15-30 minutes on changing one of the mixer/fresh air servos. The foot well is a bit more tucked in there, but normally need the same time to change. I've changed several tens of these.
Cheers,
Tore

[porsche964guy]

You would have to be really small to get at them. All I know is I couldn't and would need to remove the hood also. Good luck.

[hodol88]

Thanks for all you input. I turned on my defrost vent this cold morning (50 oF), and it started working again. Maybe, bad connection in the servo? I know that the motor is working fine now.

[porsche964guy]

That's great! Sometime my instrument lights go dim and the gauges hesitate a little. I've learned to slap the dash board a couple of times and it fixes it for 6 months. Sound a little like your problem.

[porsche964guy]

Sold: 964 624 324 00 temp. mixing flap

Still have: 964 624 903 00 Footwell flap