[BDPJR]

My '13 GTS drivers side seat heat won't stay on. Lights come on for a second then off right away. My Google search before coming here thought that a reset might work. Unplug the connector under the seat, wait 5.... that doesn't seem logical but we don't want to go to the dealer right? I'm researching where a drivers seat relay might be. Seem logical. Lastly, I bought a Durametric diagnostic tool (OBD to USB cable for ur laptop) for T-shooting some other faults and reset my service light after oil changes and other maintenance. Pricey but awesome program. Obviously a faulty seat heat condition won't trigger a dash light, but I'm hoping this tool will tell me something. I love Porsche but this bitch has been a problem since I bought it from the dealer... yes, dealer.
If anyone reading this has a known fix
Thanks for whatever u pass on.

 

[StephanPorsche]

Swap the Drivers & Passengers Seat Button, if the Drivers Side Switch works fine heating the passenger side the switch is fine. I doubt it would be a relay but you can jump it to provide continuous power and try the original button again. Having lots of experience with Porsche, VW, Audi vehicles I would guess its the actual seat heater, which you can OHM check for a short or open.

 

[wkearney99]

I could be wrong, but I don't think that the buttons are swappable in the way you're thinking. They're part of the horseshoe-shaped center console panel, and I think their signaling is done via bus, not by a on/off switch circuit.

I'm assuming you've already checked that the fuse for the front seat heating is good? I believe it's in the right-side fuse panel.

There is a connector under each seat for the heater. If you fashioned some sort of jumper you could try powering one seat from the other seat's connection. If the button works properly powering the other seat then you'd know it was the seat. But if the problem continues then it'd be something else.

From what I could see from some schematics the seat heat comes off the A/C control unit. A swap at the module would probably involve "less" jumper wire, but would likely involve poking around inside a harness connector. I don't know for certain which wires are involved at the console. The schematic just lists blue and blue/white as being used for the seats. I've only had the center console panel out once and vaguely recall there was a top center connection that might be the one.

 

[BDPJR]

Well, ck this sh!t out... before following Stephan's suggestion I had to run an errand. Hit the button for a giggle and it started working (toasty on all three levels). I realize the problem is still there. Got hm vacuumed under the seat due to a lot - a lot of dog fur. I have a service K9 that sheds 365. Started the car again and no workie. Next morning, same - same. First start of the day doesn't work. Second start of the day works. By second start I mean I'm going to drive it. I'm wondering if a long drive will do something and with that I'll be adjusting the seat as I go. Letting it sit for several hrs seems to reset it which doesn't seem logical. In the Air Force (I worked F-16 avionics on the flightline) we called this chasing a gremlin. More to follow in the days ahead....

 

[wkearney99]

I don't know how 'recessed' the wiring is up under the seat. It'd probably be worth using your phone to shoot some video taking a look up/in there.

 

[BDPJR]

Wkeamey99 - You are correct on the actual button swap, but I was going to just swap the plug underneath if possible. I would love to get my hands on a schematic for this and some other sys. Haynes and Chilton don't have Cayenne's, Hell, they don't have anything Porsche related past 1975. I made some jumper wires for another Porsche project and will use them when I can make more time to play with it. Good suggestion BTW. So, tell me about this schematic you looked at

 

[wkearney99]

There have been some bootlegged service manual pages floating around. Most of the Cayenne models through 2018 have been similar enough to allow most of the info to be applicable across different years. Otherwise an Alldata subscription is apparently a good option.

I helped the T9 guy handle creating the video for the start/stop override module. The youtube video for it was done in my 2017 GTS. At 1:44 you can see where I'm raising the center console panel that holds the AC controls.

I don't know if you can get it loose without removing the radio or not. To install the module you don't have to remove it, just raise it. If the radio is in the way you have to remove the vents to get at the radio's mounting screws. It's not "difficult" just tedious to release the clips that are inside the vents. But if you can raise it enough to see, there's several connectors that clip into it. I believe the seat heat connector is the one at the front/center end of the module. It may be possible to wiggle things loose enough to gain access to it without removing the radio. But if you're going this far into the process it's not that much more work to get the radio out of the way.

 

[wkearney99]

This is the only relevant page I could find among the ones I have. Note the bottom section, it lists the connector pin numbers in groups. I believe that's each connector, and from what little I remember seeing on mine and in other posts online, the "E" connector with 3 pins in probably that front-center one on the underside of that module.

 

[BDPJR]

I apologize for the delay. Wkerney, here's a twist. On 1st start up I needed to turn on the rear window/mirror defroster and windshield defroster. On whim.... yup, seat heat worked - all three settings. Sadly, it doesn't engage consistently. But, when it works it works well. Now I need to find the link between these switches. I'll update when I can.

 

[wkearney99]

Hmm, makes me wonder if there's been something that's gotten into the switch then. Though I have NO idea how to disassemble, let alone repair, the horseshoe-shaped center console control. If it's like the button module for the sport+ mode (the one at the rearmost part of the front center console) then it's bubble-shaped membrane buttons. Those have a metal 'cap' inside a clear membrane, that when pressed makes contact with circuit board traces underneath.

I suppose it's possible you could attempt to GENTLY separate the housing for the panel to get access to the relevant pieces and clean them up if there's any debris on them. I don't know that I'd trust spraying anything down into there, for fear of causing a short circuit. Lots of things 'stay live' in the car and you'd be asking for trouble trying to do it while it was connected.