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Discussion Starter · #1 ·
I have an issue with my drivers heated seat, if I use stage 2, I can feel the heat for a moment but it shuts off within 1min and then it will not work again until the car has been turned of and back on.
On stage 1 it stays on but doesn’t seem to be that warm.

I’m hoping it’s the control module but have no idea where it’s located

Help please
 

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My UP GTI heated seats have always been useless. On level 2 it takes ten minutes for any heat to come through and then only the slightest amount of heat is felt. Then when it goes to the lower level 1 it is just the same as being off.

Most on here say their seats are so hot they roast you alive, so there must be something wrong with mine, however my VW main dealer said they are working as they should, but i think they just checked if the switch was working, even though i told them it is the amount of heat they give out that is the fault.

I am leaving it until my next service next year when i will get the dealer to try again. Thank goodness the cars heater is excellent, nice and warm.
 

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Thinking out loud...

The real check is to measure the current being delivered into the seat, since this is the only thing that determines how hot the seat gets. It's only going to be say, 2-3 amps. You can also measure the resistance of the element...

I'm guessing that any heated seat (with 2 heat levels) has either two resistive elements which are switched in and out, or a single element controlled by a thyristor or similar to give two heat levels. The 'element' will be like those in an electric underblanket. There may also be a thermistor or similar to regulate the temperature. I suspect it's cheaper to have one element and electronics.... Does anyone know how many wires go to the seat heater? That'd be a giveaway.

Point is that if the seats had two elements that were simply switched in or out, the only things likely to be wrong are a poor or intermittent contact putting resistance in the path, or a damaged element. This doesn't quite fit the symptoms for the OP. If the seats are electronically controlled, however, then there is a good chance there is a fault with the electronics; this seems likely for both 'Testdriver' and the OP.

I have no idea where the controller lives though!
 

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Yes Steve i thought the way to check was to see how much current, amps were flowing through the seats, or if the
thermostat was working, but not being techie minded i could do nothing more than leaving it to the dealer to check. I told them it was the amount of heat or lack of it that was the fault when i first booked it in with the guy on service reception and he typed this into the computer, but on the day i had the service it was another member of staff on reception.

They said the the seats were working as they should. The switch worked and the heated seats did turn on. I said i know this but it is the amount of heat that is useless which is the fault. I asked if the amps and thermostat had been checked. He said i will ask the mastertech. He went in the back but came back rather too quickly and said yes everything has been checked and the seats are working correctly.

I must say this is my only complaint about the car. Everything else about the car is excellent including the cars heater, so i have really given up on the heated seats. What more can i do other than get them to try again when i take the car for a service next year.

There is another local VW main dealer so i could ask them to look at the seats. Also they have a 21 reg UP GTI for sale, so i thought of asking if i could sit in the car for around 10 minutes and try the heated seats. Not a test drive or even the need to start the engine, just to sit there with the heated seat on. If that cars seats were much warmer i would know mine are faulty, but if they are the same as mine i would know thats how they are. "They are all like that Sir" Do you think they would think that is a strange request? Its just making the effort to go to the dealer in this cold weather. Thank goodness the cars heater works really well.
 

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Yes an old conversation now and we all know you have extra thick long-johns! :) But I for one, am happy to believe your seat(s) are below par...

I bet your garage did not insert an ammeter to check the current, or the resistance of the element, they just pressed the switch and waited for seat to warm slightly, and said "all fine, customer wrong", as usual....

The switch doesn't control anything directly, it just sends a pulse to the controller, like a PC keyboard, which then sends a signal to one or both orange lights in the swicth body, and then turns on the heating circuit. So if the lights come on, the switch itself must be working.

The trick is for one of us to find out whether there is a thermistor in the seat controlling heat output, or if it is "open loop", as the thermistor could be the culprit.

Sorry, none of my comments helps the OP in finding the fault, or finding the control module! (well, maybe if there is a thermistor in the seat, it may help), but I think the control is done by this:

2.1.1 General description
The onboard supply control unit - J519- is fastened to the rear of
the relay carrier in the driver side.
....etc
2.1.6 Final control diagnosis of onboard supply
control unit

A final control test of the following components can be carried out
with this function:
♦ Lighting
♦ Windscreen wipe/wash system
Heating for windscreen, rear-window, seat and mirror
♦ Central locking
♦ Warning, monitoring and sliding/tilting roof
♦ Windows
– ⇒ Vehicle diagnostic tester connect and select the operating
mode “Targeted fault-finding”.
– Select the “Selected Functions/Components” and subsequently
the following menu points using the button “Skip”:
♦ Body
♦ Electrical System
♦ Diagnostic capable systems
♦ Onboard supply control unit
♦ Onboard supply control unit
 

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Thanks again Steve but that list is like a foreign language to me.

An idea has come to me which i would like to put to you. Just let me pull up my Long Johns first.

Lets say when i turn the seats on to the high setting and 2 lights show. Even though the switch shows 2 lights the seats are infact only on the low setting. Then when i press the switch to put the seats on the low setting with 1 light showing, the seats are infact off

In other words no matter what the switch says the seats are never on the high setting, they are only ever on low or off .Do you think that could be possible? The amount of heat produced would concur with that.

I am on my holidays next week so when i get back i may pop into the dealer again to mention this. I am not sure how they would check this, perhaps with VAG COM or testing the amount of amps as you said, as i guess more amps should show at the higher setting than at the lower setting.
 

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Yes, it could be that.
If so, it implies the switch is sending the correct signalling to the controller (which is then turning on the correct orange lights in the switch), therefore something is wrong with the heating circuit or power to it. We still haven't established if the seat has two heating elements or one - maybe a clue is in the connector, and a voltmeter might tell us something, according to whether the switch shows one or two lights... Anyone checking this should be certain they are not fiddling with the side airbag electrics!

NB, the text at the bottom of my last post was from the workshop manual, and was to help the OP find what might be the power control module and check what's in it...!
 

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I see we have not had any updates from anyone re if the seats have one or two heating elements or if a fix has been found for the problem.

I am back home from my hols and have seen on AT the UP GTI at the local dealer that i was going to sit in and try the heated seats has been sold. So much for that idea.

My cars heated seat felt warmer today when i went for a drive to the shops to stock up after being away for a week. The weather was a lot colder today, so i guess that makes a difference on how much heat you can feel from the seat. The cars heater is still so much better though and makes the car nice and warm.

I really cant be bothered making a trip to the dealer in this cold weather and i will be driving a lot less in the winter anyway, so i think i will wait until the cars service next year to get them to check the seats again just before the warranty ends.
 
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