No air blowing in footwells, where to start!?

[Rising_Sun]

Hi,

I've had my Cayenne S 2003 for 2 weeks and it’s a dream to drive, one 500 mile round trip and it’s an awesome machine.

I posted 2 weeks ago due to an intermittent error on the dash "PHC Failure". The car has just had a new battery and Loren advised it may need a reset. All I did was disconnect the battery earth under the seat for 10 minutes, and then reconnected it; it was as easy as that - Thanks Loren!

Another minor problem is that there is no airflow to the footwells - neither one, the mechanism for the vents and screen works fine, but select footwell only and the fan sounds like its blowing against a closed shutter valve. I've loads of receipts for the car for routine maintenance, in 2008 there is mention of "investigate lack of flow to footwells" at a Porsche centre, they recommended removal of the dash to investigate and the owner presumably adopted not to do that. I'm pretty competent with most jobs but removal of the dash sounds like a pig of a job, is there a diagnostic for this job, or can anyone advise access to the components? I was going to remove the glove box and go from there, mine is a UK car RHD, and so glove box is on the left.

I once had a Saab with a similar problem from new, it was a ball joint that was disconnected, just snapped it on and it worked, hopefully its as simple as that, hopefully its not a dash out job.... :-/

Any help would be really appreciated

[wvicary]

There is a servo that control a blend door for the footwell but I don't know which one is which on the Cayenne. I'll do some research and post back any findings.

[wvicary]

All the blend door servos are located on the left side of the main climate control air box. The footwell motor is the unit nearest the shifter housing but I have no data on DIY for replacement- sorry.

[Rising_Sun]

Thanks wvicary, I appreciate the response, If anyone knows the procedure that would be a bonus, otherwise I will do some further research, and post photos if I'm successful and fixing the issue.

[mudman2]

The one that controls the floor is a bad on to replace or at least thats what my dealer told me when the changed mine. A lot of stuff to remove to get to it and the end result is not much of an improvement. Have you manually set it to go down there to test ?

[deilenberger]

Direct it to the footwell manually (with the buttons behind the sliding panel) and then turn off all the face level vents?

Anything come out? If not - prolly that door isn't fully opening/closing.

[Rising_Sun]

Hi All, I've located the problem, quite simple really apart from the lack of space behind the dash. I located the servos, there are three I could see, and one under the dash controls the recirculation system. one nearest the shifter is the footwell, there’s one a little further up I assume that’s for the face vents or windscreen.

In order to access the servos first remove the bottom panel, one torx screw nearest the seat in the centre, then drop the panel down & detach the 12v aux sockets (there’s 2 on mine). Also detach power from the footwell light. Then remove the glove box, very simple just a few screws then is drops away. Then you can see more. If you follow the wires you see the servos, all 3 are the same basic type.

3 screws hold each one on, that’s the more tricky part as they are fiddly, but once the servo is off you can test it. Mine was dead, but once I worked it a little it jumped into life, maybe it was jammed. I them popped the cover off and you can see inside, there’s a little motor in there and a few contacts, I cleaned it all up with contact cleaner lubricated it and reassembled it. Then hey presto I had a blast of air in the footwells. So that’s the first time for 4 years +, and the dash didn’t have to come out, thankfully. If it fails again I'll get a new solenoid, I think now I know I could replace it in 15 minutes.

Hope this helps someone else, regards James

[hahnmgh63]

Thanks for the writeup, I may just check mine out too as mine only gets a small amount of air in the footwells. Possibly the servo motor is only opening the vent a slight amount.

[1schoir]

Hi All, I've located the problem, quite simple really apart from the lack of space behind the dash. I located the servos, there are three I could see, and one under the dash controls the recirculation system. one nearest the shifter is the footwell, there’s one a little further up I assume that’s for the face vents or windscreen.

In order to access the servos first remove the bottom panel, one torx screw nearest the seat in the centre, then drop the panel down & detach the 12v aux sockets (there’s 2 on mine). Also detach power from the footwell light. Then remove the glove box, very simple just a few screws then is drops away. Then you can see more. If you follow the wires you see the servos, all 3 are the same basic type.

3 screws hold each one on, that’s the more tricky part as they are fiddly, but once the servo is off you can test it. Mine was dead, but once I worked it a little it jumped into life, maybe it was jammed. I them popped the cover off and you can see inside, there’s a little motor in there and a few contacts, I cleaned it all up with contact cleaner lubricated it and reassembled it. Then hey presto I had a blast of air in the footwells. So that’s the first time for 4 years +, and the dash didn’t have to come out, thankfully. If it fails again I'll get a new solenoid, I think now I know I could replace it in 15 minutes.

Hope this helps someone else, regards James

James:

Thanks for sharing the solution and providing the details. :thumbup:

Regards, Maurice.

[deilenberger]

Thanks for the writeup, I may just check mine out too as mine only gets a small amount of air in the footwells. Possibly the servo motor is only opening the vent a slight amount.

Please update us on your results.. I've had the same complaint on my '06.. my tootsies get cold in cold weather. There is air coming out the vents (which are awfully small) - but not a lot of it.. One thing I noticed - I can increase the volume of air by manually selecting the footwell, then closing all the face-level vents (the outer ones still are delivering hot air, even when not selected.)

[wvicary]

Thanks for the writeup, I may just check mine out too as mine only gets a small amount of air in the footwells. Possibly the servo motor is only opening the vent a slight amount.

Please update us on your results.. I've had the same complaint on my '06.. my tootsies get cold in cold weather. There is air coming out the vents (which are awfully small) - but not a lot of it.. One thing I noticed - I can increase the volume of air by manually selecting the footwell, then closing all the face-level vents (the outer ones still are delivering hot air, even when not selected.)

My Cayenne is the same, no fault codes in the system and seems to have the same amount of air flow from the footwell vents as other Cayenne I compared it to. I just assumed it's normal... which is poor. Another note: the blower fan is much louder when footwell is selected.

[XR4Tim]

I imagine it may be easier to get at those servo motors in a right-hand-drive vehicle, assuming they are on the left side of the dash. They can be somewhat challenging on the left-hand-drive cars with the steering column, control modules, and relays in the way. Still no need to remove the whole dash.

[burgixxl]

Hi All, I've located the problem, quite simple really apart from the lack of space behind the dash. I located the servos, there are three I could see, and one under the dash controls the recirculation system. one nearest the shifter is the footwell, there’s one a little further up I assume that’s for the face vents or windscreen. In order to access the servos first remove the bottom panel, one torx screw nearest the seat in the centre, then drop the panel down & detach the 12v aux sockets (there’s 2 on mine). Also detach power from the footwell light. Then remove the glove box, very simple just a few screws then is drops away. Then you can see more. If you follow the wires you see the servos, all 3 are the same basic type. 3 screws hold each one on, that’s the more tricky part as they are fiddly, but once the servo is off you can test it. Mine was dead, but once I worked it a little it jumped into life, maybe it was jammed. I them popped the cover off and you can see inside, there’s a little motor in there and a few contacts, I cleaned it all up with contact cleaner lubricated it and reassembled it. Then hey presto I had a blast of air in the footwells. So that’s the first time for 4 years +, and the dash didn’t have to come out, thankfully. If it fails again I'll get a new solenoid, I think now I know I could replace it in 15 minutes. Hope this helps someone else, regards James

Do you have picture of where the servos located ?

So to summarize, basically removing the glove box is enough ? The center console does not need to be touched ?

My problems seems to be the servos vor the middle located vents.

 

Regards

Burkhard

[hahnmgh63]

burixxl, you would only remove the glove box if you were working on a RHD car to get at the 3 Servos. On left hand drive it is a tougher job as the HVAC layout doesn't change so it is still the Left side which now makes it more difficult as the Steering column is partially in the way.  If you are getting foggy windows without the A/C running then the right side is where the fresh air Servo is located, it is close to and just above where the Cabin (Pollen) filter goes.

Edited July 4, 2015 by hahnmgh63

[burgixxl]

burixxl, you would only remove the glove box if you were working on a RHD car to get at the 3 Servos. On left hand drive it is a tougher job as the HVAC layout doesn't change so it is still the Left side which now makes it more difficult as the Steering column is partially in the way.  If you are getting foggy windows without the A/C running then the right side is where the fresh air Servo is located, it is close to and just above where the Cabin (Pollen) filter goes.

What I figured out so far, that for the middle vents, there is a middle left servo and a middle right servo. Those are on the left and right side, so I have to do both, remove glove box and Steering column space.

I have a LHD Cayenne. Saw some figure for a touareg, where there also removed the complete dash. Is this really needed ?

How mich hours to work on I need to calculate ?

 

One other major question. There are 6 servo motors in total. Looking at the spare catlog of Porsche, they have all different number, but I do not think, that there are all different ?

And also read in another forum, that a VAG COM tool is needed to set the servo in service mode. Is this mandatory ?

[wrinkledpants]

Thanks for the writeup, I may just check mine out too as mine only gets a small amount of air in the footwells. Possibly the servo motor is only opening the vent a slight amount.

 

Have you checked whether you can do the output tests with Vagcom?  That should tell you if the flaps can move their full range.

[burgixxl]

 

Thanks for the writeup, I may just check mine out too as mine only gets a small amount of air in the footwells. Possibly the servo motor is only opening the vent a slight amount.

 

Have you checked whether you can do the output tests with Vagcom?  That should tell you if the flaps can move their full range.

 

Have no VAG Com :-(

[Loren]

Durametric, PIWIS, or PIWIS 2 can all do diagnostics on the HVAC system.

If you do not have access to one of these find a shop that does. Everything else is just guesses or expensive dis-assembly that may not be required.