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Hi All. Has anyone had any problems with the heated seats? My D2 cc has cloth heated seats but the driver's side has stopped working.

The passenger one is ok and the button still lights up and the dashboard shows it's on.

Any ideas, if I took the seat out would that mess anything else up?

Thanks
 

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First of all, check the fuses - Fuse 34 and 35 in the under-seat fuse box run the heated front seats. If the LED and display icon don't come on when you press the button, it means the Climate Control Module knows it can't talk (or is getting no response) to the Seat Heating Module (it controls the seat heating by sending LINbus messages to the SHMs).

If it's not the fuses, it could be a fault in the SHM itself, a broken heater element, or possibly the temperature sensor (the SHM controls the temperature by reading from a sensor embedded in the seat squab). If the sensor has failed or one of the heater elements is faulty the SHM probably rejects any requests from the CCM to turn on the heating (i.e. it fails safe). There are diagnostic test functions in VIDA to check the SHM functions, and faults would show up as error codes from the CCM, but that probably requires a trip to the dealer.

If you do want to take the seat out, there is the risk of the airbag going off when the wiring connector is disconnected (there is a large rectangular connector with a spring-loaded bolt holding the two halves together which connects the seat to the body loom). Leave the ignition off for 30 minutes and probably disconnect the battery too before disconnecting the seat connector.
 

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Excellent info.

My issue.

Drivers Heated seat not working.

Vida tells me that the system went faulty about 6 weeks ago.

Basically, it is in fail safe mode.
It is complaining CCM-B103601 - Right Front Seat Heater Element - General Electrical Failure. Front Seat, Seat Heating Does Not Work or too hot, UW.
Tells me to CHECK SEAT HEATING MODULE (SHM)


Open Circuit on the Cable Between SHMR and heating coil.
Cable between SHMR and heating coil is short circuited to Ground
Cable between SHMR and heating coil is short circuited to voltage.






I have had a good look under the heat and the rear of the seat and can't see anything out of the ordinary.
I have also checked the blocks and connections to the seat block, and what I assume is the Module.
I have also checked the Fuses for both seat elements.


The dash buttons function as normal as when I'm looking at the Live Vehicle Communications. It states fault for the drivers seat module.


Not too sure what to check/replace next.

Happy to take the seat out and investigate if I have to?

Please help?
 

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Excellent info.

My issue.

Drivers Heated seat not working.

Vida tells me that the system went faulty about 6 weeks ago.

Basically, it is in fail safe mode.
It is complaining CCM-B103601 - Right Front Seat Heater Element - General Electrical Failure. Front Seat, Seat Heating Does Not Work or too hot, UW.
Tells me to CHECK SEAT HEATING MODULE (SHM)


Open Circuit on the Cable Between SHMR and heating coil.
Cable between SHMR and heating coil is short circuited to Ground
Cable between SHMR and heating coil is short circuited to voltage.

I have had a good look under the heat and the rear of the seat and can't see anything out of the ordinary.
I have also checked the blocks and connections to the seat block, and what I assume is the Module.
I have also checked the Fuses for both seat elements.

The dash buttons function as normal as when I'm looking at the Live Vehicle Communications. It states fault for the drivers seat module.

Not too sure what to check/replace next.

Happy to take the seat out and investigate if I have to?

Please help?

Sounds like it might be the wiring in the heater element matrix in the seat itself is either broken (open circuit) or shorting out. It's the RHS seat, which is the one that gets sat in the most. In the electrical troubleshooting part of VIDA it should give you a pinout for the SHM connector, and a suggested resistance value for reading across the supply and return feeds for the heater element that should narrow down the fault.


This is the problem with VIDA - it gives you all the information and access to diagnostics, but without the experience (in this case of auto electrics) it doesn't really help you that much and can lead you on wild goose chases swapping modules (which in most cases is what happens in dealerships).
 

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Sounds like it might be the wiring in the heater element matrix in the seat itself is either broken (open circuit) or shorting out. It's the RHS seat, which is the one that gets sat in the most. In the electrical troubleshooting part of VIDA it should give you a pinout for the SHM connector, and a suggested resistance value for reading across the supply and return feeds for the heater element that should narrow down the fault.


This is the problem with VIDA - it gives you all the information and access to diagnostics, but without the experience (in this case of auto electrics) it doesn't really help you that much and can lead you on wild goose chases swapping modules (which in most cases is what happens in dealerships).
I'll have a look, get the old multimeter out and check the elements for starters. Hard to access though.
 

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I have spare seat heater modules for both front seats in my garage if you need one I could be persuaded to sell.

I bought heated front seats from a scrap yard and retro fitted then into my car which does not have seated seats so could not use the fancy electronics and just have an old fashioned switch and thermostatic relay.
 

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I have spare seat heater modules for both front seats in my garage if you need one I could be persuaded to sell.

I bought heated front seats from a scrap yard and retro fitted then into my car which does not have seated seats so could not use the fancy electronics and just have an old fashioned switch and thermostatic relay.
Impressive modification.

I'm going to trace the electronics and take measurements of the elements etc and will let you know.

I'm assuming it is likly to be a broken element/connector/damaged thermostat.

I did have he bottom seat frame replaced by Volvo under warranty about a year or so ago, so they may have messed up or left a cable lose which has become trapped etc..

Thanks for the diagram, and will let you know. Thanks
 

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Impressive modification.

I'm going to trace the electronics and take measurements of the elements etc and will let you know.

I'm assuming it is likly to be a broken element/connector/damaged thermostat.

I did have he bottom seat frame replaced by Volvo under warranty about a year or so ago, so they may have messed up or left a cable lose which has become trapped etc..

Thanks for the diagram, and will let you know. Thanks
From the wiring diagram, it's component 9/19 you should be looking at (the RHS seat squab heater element and thermistor).

I checked my copy of VIDA and there's no pinout or signal info for the SHM connectors, unfortunately. From the wiring diagram the SHM has 3 connectors, A, B and C.
Connector A is the Power and LINbus comms:
Pin 1 is Ground (Black)
Pin 2 is LINbus (Blue)
Pin 4 is Vss (12V) (Red)
Connector B is the seat squab connection
Pins 1 (Grey) and 4 (Brown) are the heater element
Pins 2 and 3 (both yellow) are the thermistor
Connector C is the backrest connection
Pins 1 (Red) and 2 (Yellow) are the heater element.
They should look like this - top connector is B, A is lower right and C is lower left.


You are looking for a low resistance between pins 1 and 4 of connector B. There should be no continuity between either pin and Ground though.

There is a wiring loom in the seat between the SHM and the other components. The seat connects into the floor loom via a large 20-way connector clamped together with a bolt 9as the airbag and seat tensioner signals are carried through it). The Power, Ground and LINbus signals for the SHM come through that into the seat loom and then into Connector A of the SHM. The seat squab element/thermistor should also have a 4-pin connector into the seat wiring loom, and the backrest element will have a 2-pin connector into the loom.

Taking the seat to work on out is going to be your best bet. Take care dis/re-connecting the 20-way connector as it can lead to the airbag or tensioners triggering - the usual procedure is to disconnect the battery and leave it for 20 minutes before disconnecting the seat.

I suspect the lower seat frame replacement may be the source of your problems.
 

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From the wiring diagram, it's component 9/19 you should be looking at (the RHS seat squab heater element and thermistor).

I checked my copy of VIDA and there's no pinout or signal info for the SHM connectors, unfortunately. From the wiring diagram the SHM has 3 connectors, A, B and C.
Connector A is the Power and LINbus comms:
Pin 1 is Ground (Black)
Pin 2 is LINbus (Blue)
Pin 4 is Vss (12V) (Red)
Connector B is the seat squab connection
Pins 1 (Grey) and 4 (Brown) are the heater element
Pins 2 and 3 (both yellow) are the thermistor
Connector C is the backrest connection
Pins 1 (Red) and 2 (Yellow) are the heater element.
They should look like this - top connector is B, A is lower right and C is lower left.


You are looking for a low resistance between pins 1 and 4 of connector B. There should be no continuity between either pin and Ground though.


I suspect the lower seat frame replacement may be the source of your problems.

Many thanks for this info, and the other chap for the diagram.
I was looking at this in work today and fully understand and how I'm going to test it and how it all works.
I am surprised there is no thermistor in the backrest for safety.

If I find all the resistances of elements and readings from the thermistor to be ok, can I swap the SHM from left to right? I am assuming YES, but have not checked part numbers.

Bottom frame, yes it wouldn't stay in place back right of the seat.. Was moving up and down and not locking.
Volvo looked as I worried it may be a MOT failure and they said the weld was cracked and replaced the seat.
They actually replaced the bottom frame and swapped the rest over. Did work ok since this repair, but not now.
If an element is open circuit, can they be replaced? Like are they slide in panels?
 

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I am surprised there is no thermistor in the backrest for safety.
[//quote]
The temperature is controlled by regulating the current flowing through the heating elements. The same current is supplied to both. The backrest element is slighly larger than the seat squab, so it should be cooler for the same current. Also, you are more sensitive to temperature through your backside than your back due to the distribution of nerve endings.
If I find all the resistances of elements and readings from the thermistor to be ok, can I swap the SHM from left to right? I am assuming YES, but have not checked part numbers.
The SHMs have different part numbers for left, right and rear (if fitted). This is because they all have different IDs on the LINbus network (and are probably coded into the CEM's ID list too), so you can;t really swap them over (getting to the module in the seat that is faulty is going to be a bad enough job). VIDA is telling you what it wrong anyway - it's almost certainly either a loose connector from the seat pad into the seat loom, or the seat pad has got a broken element.
Bottom frame, yes it wouldn't stay in place back right of the seat.. Was moving up and down and not locking.
Volvo looked as I worried it may be a MOT failure and they said the weld was cracked and replaced the seat.
They actually replaced the bottom frame and swapped the rest over. Did work ok since this repair, but not now.
If an element is open circuit, can they be replaced? Like are they slide in panels?
The heater element pad sits between the foam cusion and the upholstery cover, which needs to be removed from the frame to get at it. Lots of split rings holding it on I suspect, and then it has to be stretched back over the seat afterwards. It's what they will have done to replace the seat frame.
 

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Well, I have gone to the extreme and today purchased a replacement drivers seat!!!

To be honest, it was £65 and is like new. It also has the additional Lumbar and Front seat adjustment, like a up down leaver at the underside of the front of the seat. So it's an upgrade.


With my old seat out I'll give it a good look over and test the elements and thermostat. I figured as the cables are all sound and secure one of the elements is broken and to pay for replacements and then stripping the seat down, it may not be worth it.

I also get my old seat which I'll modify for the office as a desk chair!

Another project.

I'm changing it over tomorrow, cables are the same. Will disconnect the battery and wait half hour as the seat has two explosives in that I don't want going off.

I'm relatively happy with this solution. :)




All Done TODAY and I'm really happy with the outcome.
My driving position is now amazing. The front lower adjust that is new has made such a massive difference.
I have always found the clutch position to be difficult in the V40, either too far away, or too high.

I have now adjusted the chair with the extra options of this chair and it's like driving a new car.

That and the heated seat is now working!!
No airbag issues or warning either.


One other small addition which makes my car unique if anyone can spot it on the picture!

 

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great job I think your car must be a bit later than ours as we have the lowering front which is brilliant but certainly not that lovely big R yet another cost cut around that time, but ours is a lux so perhaps that's it
 

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Well, I have gone to the extreme and today purchased a replacement drivers seat!!!

To be honest, it was £65 and is like new. It also has the additional Lumbar and Front seat adjustment, like a up down leaver at the underside of the front of the seat. So it's an upgrade.


With my old seat out I'll give it a good look over and test the elements and thermostat. I figured as the cables are all sound and secure one of the elements is broken and to pay for replacements and then stripping the seat down, it may not be worth it.

I also get my old seat which I'll modify for the office as a desk chair!

Another project.

I'm changing it over tomorrow, cables are the same. Will disconnect the battery and wait half hour as the seat has two explosives in that I don't want going off.

I'm relatively happy with this solution. :)




All Done TODAY and I'm really happy with the outcome.
My driving position is now amazing. The front lower adjust that is new has made such a massive difference.
I have always found the clutch position to be difficult in the V40, either too far away, or too high.

I have now adjusted the chair with the extra options of this chair and it's like driving a new car.

That and the heated seat is now working!!
No airbag issues or warning either.


One other small addition which makes my car unique if anyone can spot it on the picture!

is it the front pouch ?
 
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It's not the pouch, it's the R-Design Embroidery on the seat which I always thought was a class touch that vanished in 2014.

I have now have a drivers seat with it, and a passengers without.

One of a kind. :)
 

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I am having a similar problem with the drivers side heated seat not working on my 2012 D3 SE V40. The control works as normal and I get three red bars on the display, VIDA is reporting the same error as above (General Electrical Failure).

Using the information kindly provided in this article so far I have metered the base and back heating pads with strange results... the back is around 0.5 ohms and the base around 10 ohms. 10 ohms seems a little low as it gives an output power of around 15 watts (I was expecting 25->30) but 0.5 ohms seems too low. Does anyone know what the resistance of each pad should be? I can't find it in VIDA, I guess I could just meter the (working) passenger side.

Any suggestions appreciated - Richa
 
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