VW Bora 2000 1.9 TDI: Troubleshooting Passenger Seat Heating Issue - Pin Voltage & Switch

Hello forum users.
Please help. My problem is the lack of passenger seat heating. I checked the simplest thing - mats (I connected the passenger seat to the driver's seat harness and it's ok)
I focused my attention on the switch regulating the heating power of the chair.
Measuring the tension on the ankle, I found that
pin 1 no voltage
pin 2 no voltage
pin 3 no voltage
pin 4 + plus 12 v
pin 5 + plus 12v
pin 6 - minus (ground)
And so the voltage on the ankle looks without the switch plugged in.
However, after plugging in the switch, pin 3 appears + plus 4.7v.
I also checked the cube for heating the driver's seat and the voltage looks similar with the only difference that after plugging in the switch No. 3 there is + plus 12v voltage and the seat heats up.
Thinking that the switch might be broken I swapped them. Unfortunately, it did nothing. Still on the passenger ankle on pin No. 3 is + plus 4.7v.
Does anyone with forum members have any idea where the problem lies?
Below is the photo of the cube itself

Not with the meter and the control, measure to see the load response and wanting to give up a diagram, because hardly anyone will know what pin 1 is responsible for, etc.

Thermistor to check.

It has no pattern.


Thermistor or element on the heating mat. But the mats are good because as I wrote above, I connected the passenger seat under the driver's seat beam and began to heat. So no thermistor in mats and no mats

I'm sorry, I didn't read.

Cool, nothing is happening. I'm just afraid that something could happen to the beam under the dashboard and that would be the worst that could happen.

There is a diagram in the network, or someone on the network will help.

That's why I wrote here asking for general help. If I could handle it, I had a diagram and any idea of the cause of the failure would not write a post

Here's the diagram, check the power supply, not a meter, just a 21W bulb or larger.
https://www.elektroda.pl/rtvforum/topic2066790.html

Remove both heated seat switches. You are not sitting in any armchair and they both have the same temperature.
You are making a measurement with the switches removed from the installation plug between 3 and 6.
The results should be similar.
If they are not a damaged thermistor in the seat and usually a broken wire at the thermistor, although you say that there is something or something not connecting on the wire between the thermistor and the switch, e.g. broken wire coming from the floor or rotten wire.
I would also measure the resistance on the seat plugs after disconnecting them between the brown and black and white wires.
After these two measurements you will see exactly where the problem is.
You have different voltages between 3 and 6 between the seats because the switch has a different resistance from the seat so the passenger side switch does not heat the seat because it thinks it has the right temperature to set.
If you cut the cable from pin 3 between the plugs of the switches, the driver's seat will stop heating.
I hope you understand what I mean.

Thanks for the hint. I will cover everything you wrote on Saturday and let you know what the situation is. I just still don't get one thing. Why on pin 3 there is plus 4.7v in the passenger seat and in driver's seat on pin 3 is plus 12V. Both seats are disconnected from the bundles of wires coming out of the floor so the voltage does not flow on the heating mats in the seats

pedro1971 wrote:

plus 4.7v appears in the passenger seat and in the driver's seat on pin 3 there is plus 12V

Maybe it sticks to the ground somewhere, even due to moisture in the floor.
Unplug the switch and check with a small light bulb to see if it will come on connected to
pin3 and plus. Disconnect the seat of course.

Hello.
The case is resolved.
The harness wire was just behind the floor grommet. Probably from moving the chair.
Thanks to everyone for help