Test the seat heating

[Racataian]

Hello,

can anyone tell how to test the continuity of the seat heating elements with only access to the electrical plug? An electric diagram would help me

Thanks!

 

[wokwon]

Hi Racataian,

See attached.  I'm assuming you have climatronic.

 

Hope this helps.

 

 

[Racataian]

Thanks for this picture i will check continuity. What program is this coming from ? I would need also the pins configuration for the J774 unit, if I don't ask too much

Thanks! 

 

[wokwon]

The program is ELSA.  It's VW's service database.  There is an online version that you can pay to access.  There are other ways to get an offline version but the forum tends to delete posts that explain how to get them.

[wokwon]

14 hours ago, Racataian said:

I would need also the pins configuration for the J774 unit, if I don't ask too much

Thanks! 

 

 

 

Sorry I don't have a pins configuration diagram, but you can figure it out from the above picture.

 

The J774 unit, you can see the wire that supplies power to the heating elements. Where that wire leaves the J774, you can see the writing "T8j /5".  T8j is the connector, /5 is pin 5.

 

Below that you can see 1.5  li.  1.5 means 1.5mm^2 cable (quite thick) and li means purple.  You you're looking for an 8 pin connector, with a thick purple wire coming out.  That will be pin 5.

 

Follow the wires like that, from the module plug, to the plug on the seat wiring harness, testing continuity through each.  Also, don't unplug the seat airbag wire as you may store a code/error that is difficult or impossible to clear from the system.

[Racataian]

Thanks for the info, I bought ELSA from Ebay,now I need to find a computer that has a 32b Windows(mine is 64b). I will check the continuity for sure. My problem is that both seats stopped working at the same time and I believed that maybe the J774 unit broke down so I replaced it but without any results. Now I want to check continuity for both seats, do you have the similar picture for the right seat? I  know it uses the same J774 unit but different pin, if not I will check also for a thick cable vs ground .

If all these don't make results then I can suspect the temperature sensors or in worst case the command from the seat heating switches - wire 13

BTW: from J774 the power goes through a 1.5mm cable to the next plug then continues through a 1mm cable - doesn't make any sense 

Edited 4 May, 2017 by Racataian

[wokwon]

I run mine in a hyper-v VM so I don't have to worry about maintaining a computer.

 

Passenger diagram is below.

Quote

BTW: from J774 the power goes through a 1.5mm cable to the next plug then continues through a 1mm cable - doesn't make any sense 

 

Yes, the diagram shows this as well.  Oddly, the passenger side one does not step down in wire size according to the diagram below.  

 

Good luck.  If someone near you has VCDS then a scan may reveal the fault.  The units tend to have a lot of self-diagnosis built in.

 

 

Edited 6 May, 2017 by wokwon

[Racataian]

Many thanks,

I have ran a diagnostic with VCDS but nothing related to this failure

[Racataian]

I had a little time and did some measurements:

both seat have continuity - driver side is 2.2 Ohms, the passenger seat is 3.2 Ohms - don't know why the difference

 

The switches from climatronic J255 work and not too much, meaning, depending on the intensity of heating I set, I get input on the seat heat controller J774: 11V, 9V or 6V for the driver seat but for the passenger seat I get level 1-10V, level 2- 11V, level 3- 7V - again doesn't make any sense

The seat heating controller J774 receives power so the fuse is ok but it does not output any power to the seats

 

I need to check the G60 temperature sensor- I expect to get a value on the Ohm scale, I think it's a thermal resistance. Indirectly I believe these sensors are ok because they are connected to climatronic and the climatronic would not send any command to the seat heat controller if the temperature sensors would be damaged

 

At this point all point to the seat heating controller even though it is new...

 

[wokwon]

Quote

both seat have continuity - driver side is 2.2 Ohms, the passenger seat is 3.2 Ohms - don't know why the difference

 

Realistically, that's all you'll be able to test with a multimeter.  You have established that the elements are at least not broken or shorted.

 

Quote

passenger seat I get level 1-10V, level 2- 11V, level 3- 7V - again doesn't make any sense

 

I'd expect that the output is pulse width modulation or pulse density modulation; you'll get weird readings with a high impedance multimeter.  Better off checking with a CRO or DSO.  You could use VCDS output tests on the module to command the outputs on or off.

 

Quote

I need to check the G60 temperature sensor- I expect to get a value on the Ohm scale, 

 

I'd expect that it's a 1wire type digital sensor like a Dallas DS18B20.  Thermistors are so 1980s.  You should be able to see the reading of this sensor in VCDS using measuring blocks.

 

[Aceskoda42]

Hello all, sorry for reopening an old tred, 

 

I currently installing heated seats into a mk2 superb and I found this tred when searching for wiring diagrams. 

Hopefully some can help me ;

On the above diagrams there is a green/black and green/ blue wire connecting the control unit to the switches , these are .5 gauge wires . There shown to be linked with a heaver 1.5 gauge wire of matching colours, these wires come from the thermal control within the seat. 

Are they simply joined together with connectors at points B431 and B 645? 

I'm concerned to join because of the considerable wire gauge difference. 

 

Cheers 

[sen7]

Hi there. Since i'm currently dealing with the issue and this topic is top ranking in search engines i want to share info that i gathered so far.

A. Some say that the relay J774 could be on the driver side or on the passenger side. First you must be clear is it left wheel or right wheel car. Second does it have back seat heating or not. 

B. Let me post some photos of the cables under my seat and of the heating element. Number 1 is the 4 pin connector or 4ag on the diagram. Notice the pink wire! Number 2 is for the backrest. You can see how the cables and convectors look at the next photos of the heating elements. See the white piece of tape right next to the connector ? You can use it for reference when looking for the cable under the seat.

 

 

C. Here are two videos from the net that may be useful also.
 

 

 

[sen7]

Photo of J774

https://catcar.info/audivw/?lang=en&l=c3RzPT17IjEwIjoiQnJhbmQiLCIyMCI6IlNLT0RBIiwiNDAiOiJTdXBlcmIgRXVyb3BlIiwiNTAiOiIyMDEwIiwiNjAiOiJFbGVjdHJpY3MiLCI3MCI6Ijk2MzAwIn18fHN0PT03MHx8YnJhbmQ9PXNrfHxtYXJrZXQ9PUNafHxtZGw9PVNVUCAgfHxFcGlzPT02MzJ8fEVpbnNhdHo9PTIwMTB8fE1haW5Hcm91cD09OXx8QmlsZHRhZmVsPT05NjMwMHx8R3JhZmlrPT0wOTYzMDA2MzI%3D