Both heated seats stopped working.

[marbab]

Hi , I have Leon 2006 Stylance 1.9TDI. About a month ago heated seats stopped working at the same time. Before I start checking (changing) the mats I checked the fuse (number 37 in my car) it seems to be ok. Also checked and cleaned the connectors under the seats. VAG is not reporting any fault. Could you please advise if any of the relays is responsible for the heated seats?
I know that in some models they are, but looking at the manuals for my car it doesn't say anything like that (only fuse 37 - 30A).
Do you have any other suggestions?

Many thanks

 

[380bhpdaily]

Hi I’d put 12v to the plug of the heating element see if it turns on if it does then work your was back on the wiring testing at each joint till you find the problem. Hope this makes sense.

 

[marbab]

thanks for the answer. Good idea, I can try either that way or check the voltage after switching the seats heating on. Would anyone please be able to advise which exactly wires do I need to check, so I don't have to take the seats out? I know the yellow connector is definitely airbag. Please see photos attached. thank you

 

[380bhpdaily]

It’s the big plug the smaller two plugs are like you said air bag and seat belt pre tensioner you definitely don’t want to mess with those as adding 12v to that will end up causing a major ejecto seat situation.
Use a multi meter on each of the wires one at a time with the Ignition off and on to see if it’s 12v is there when the key is on. But this might not work if the actual fault is a relay or feed issue.

 

[marbab]

Checked it today and looks like power goes to the seat when switching the seat heating on, so I took passenger seat out and dismantled it. It's much more complicated then I thought. There are many wires going from the plug. some of them go to the side of the seat, some go to suport heat (and that's another surprise as I didn't know the all the support is heated not just the bottom part). After checking the circuits it looks like: support mat is ok, base side mats are ok. Base centre matt is not ok, but the wires are ok, there is a small part ( no idea what is is) - in red circle on the picture, that seems to be knackered. Another thing with no circuit is a tape - seat occupy sensor. As the wires are all good, I would rather replace the broken elements (if possible). Has anyone got any idea of what these not working parts are, and where can I get them? The other good thing about today is I managed to wash the covers properly and they look like new now

 

[Woody_72]

The bit circled in red is probably a thermistor to monitor the actual temperature.

 

[marbab]

The bit circled in red is probably a thermistor to monitor the actual temperature.

thank you. Can I connect the matt to 12v without thermistor (connecting 2 blue wires) just for 1 min to check if the matt is heating? Or would it damage the matt?

 

[Woody_72]

Don't think it would cause any issues for a minute. It would just apply the usual amount of heat but without any control.

 

[marbab]

Thanks. Managed to repair both seats. It was faulty thermistor in passenger's seat and burned matt wire on a driver's seat. I repaired them, put everything back and tested and all worked perfect. This cold morning I was excited going to work and finally enjoy the heated seats again and... it doesn't work again. I don't get it. What could go wrong this time? It worked yesterday evening...

 

[marbab]

update: later in the evening, and this morning everything works fine again. I don't get this. Does the outside temperature have anything to with it? It was only 1°C when it didn't work and around 10 when it worked.

 

[380bhpdaily]

It shouldn’t matter what the temp is outside for this system.
Tough one tho maybe something is still loose in the system and when you sit in the seat it’s breaking connection.