The manual confirms the thread. If it were both seats, I would suspect the temperature sensor. Given it is driver's side only and the problem evidences on both heat and cooling, I suspect an electrical problem with the seat (perhaps a fuse?).
There may be service manuals available....but I don't have one. Good luck and let us know how it turns out.
Edit: Our illustrious K-Man S recently made available a technical guide for the latest Cayenne (may or may not be relevant to the 958) at this link: http://www.planet-9.com/downloads.php?do=file&id=391
There is interesting reading beginning on page 141. Here is an excerpt:
Regulation of the seat heating and seat ventilation depends on the relevant values of the
temperature sensors (NTC) in the seat surfaces and on the passenger compartment
temperature (infrared measuring principle). However, before the selected function (heating
and/or ventilation) is executed, the energy management system in the gateway
checks whether the request for seat heating or seat ventilation can be met. The engine
running signal or the information that the ignition is switched on (terminal 15) is required
in order to check this.
If the available energy does not exclude the possibility of using seat heating or seat ventilation,
the gateway sends corresponding information (bit) on the CANMMI. As soon as
this information is detected by the individual operating and air-conditioning units, the
desired function or setting is activated directly by the air-conditioning system control unit
(operating and air-conditioning unit).
Still thinking battery or fuse could be the culprit.
This is a fairly low tech problem compared to so many others that could happen. I have not seen this problem or the service manual but here is what I would envision. Check the fuse and relay first. Check the switch. Pull the seat and see if there is voltage to the fan motor. This can't be expensive for a competent shop to troubleshoot and fix. There shouldn't be any parts involved that would be very expensive. JMO. But Porsche does have a way of surprising us with added costs, as do many other OEMs.
View attachment 62061View attachment 62061
porsche cayenne 958 Driver's seat ventilation stopped working even the heat is not working .
Just when i click to start they start for a 5 second and they stop.
thank you in advance
Any update on repair been having the same problem on my 2012 Cayenne s. Also driver seat ventilation and heat work while not sitting on them But as soon as I apply pressure to the seat it cuts them off.