Heated Seat Repair

[Steve S.]

Dear All,

Well, for my next project I thought that I would tackle the non-working, passenger side seat, especially as the cold mornings seem to be with us (at last ??) After an initial investigation, it transpires that both seats don't work. Well it's hardly a blow but if you've got 'em you may as well have the benefit! On further investigation with the AVO and a bulb it looks like it is both seat squab elements that are at fault, which is bleeding typical as it looks like the the most involved of jobs. The backrest elements show continuity, as does all the connecting wiring, the switches seem to operate and have their rheostat function,whilst the relays (under the seats) "look" ok...nice and shiny inside with moveable points. It is just the squab elements that have an "open" circuit reading. Now I'm not too sure of my ground here as there are 4 wires leading to the seat bottom element I am led to believe that one pair is for the element ,the other for the thermistor (a kind of temp.regulator ?) but as they are supposed to be in series (i.e. one break and the lot fails) I don't quite see how it is wired up.Anyway unless anyone suggests not , I'll assume it is that the heating element that has broken and / or the thermistor has become detached. As this further investigation requires some leather upholstery skills etc. I was hoping for some advice from the knowledgeable amongst you that may have have had the nerve/ skill/ confidence/ sheer stupidity! to have tackled this before. I understand that replacement elements are available (at a horrendous price) so I am hoping to repair any break with bridging wires.

Anyway your input,as always, is greatly appreciated.

Regards to all,

Steve S.

[tiny]

From my experience with heated seat elements (used to work for a company who were agents for BE-GE a swedish manufacturer) The heated pads were virtually repair proof.

 

It may be totally different in the galaxy, but on the seats i sold, any fault with the heat pad itself usually involved a broken or burnt through heating element. On fabric seats this often resulted in a hole or singe mark!

 

 

Good Luck though :(

[Steve S.]

Well, I have made some progress today! I've stripped the seat down to reveal the heating element on the squab.(I am taking a photo record as I go so it may appear on here eventually depending whether I'm successful or not!) I discovered a single break in the element which I have soldered up and taped. I now have continuity on this element circuit. There is however, a slight burn mark underneath the thermistor, and, when reconnected up (temporarily) the the unit doesn't heat up...oh tits! So, assuming it's the thermistor at fault, can anyone with a degree in physics point me in the right direction for a replacement with the correct specs?!!! (It's a metal disc like a watch battery with the wires soldered on either side)

At the mo. the avo shows open circuit, so I'm assuming this is knackered and wouln't work under other cicumstances eg if it heated up?

Cheers for now,

Steve S.

[NikpV]

sounds more like an older style thermal cut out/fuse - seen them in power brick type power supplies - wonder if you could replace with an axial moderm thermal fuse

 

see examples from maplin here

[NikpV]

or something like this

[Steve S.]

Hi NikpV,

Yes, I saw some of those but I have no idea whether they would do the job or not. I've looked at RS components too, they have something that looks "similar" ie rswww.com item 198-898 etc. but again I've no idea. I've checked the whole of Google this evening, and not one entry mentions the actual type or a supplier. I'm quite cheesed off that I can't get a definitive answer to this, after all somebody somewhere in the world must have fitted one of these at some time in the past even if it's some dozy bloke in Portugal (no offence intended!) on the assembly line!

I suppose I could by-pass it somehow and just switch it off when my arse catches fire!

Cheers

Steve S.

[NikpV]

rather than that I would try an axial one at 71p each its hardly a massive outlay - try a few different temps with the squab disembled - make sure that it lies parallel with the element - wire it in place - :)

[Steve S.]

Dear NikpV,

Thanks for your suggestions.Interestingly, the element wire passes directly over the metal disc of the the thermistor so it should provide a pretty accurate reading.Are not the temp.specs of the maplin components too high? If one doesn't roast one's arse ,it'll likely get scalded , we're near the boiling point of water here before it cuts out! I don't know whether it is the right sort of component as it works once only as a cut out. I imagine the original component sends info continuously to the relay or am I talking out of my burnt bits :)

Cheers

Steve S.

[NikpV]

Without seeing how its wired I couldn't tell, from my initial interpretation I got the impression that the 'component was in line with the heating element so assumed that it was a thermal cut out - permanent if the pad got damaged and too hot, in other words the resistance of the pad was such that it would run continually from the 12v supply - loosing all the energy as heat (at its raised temperature). Does it conect to the relay and so forms the temperature sensing part of a thermostat.????

[Steve S.]

Dear NikpV,

As I intimated, electronics is not my strong point! As far as I can remember the seat base has 4 wires going to it....2 go to the element, and two to the thermister.They lead back to a 6 way connector,the other two wires of which feed the backrest element (which has no seperate thermister of its own)It gets complex here ,I'll check in the morning, but there are connections to the relay,and then onward to the 4-way connection to the loom. You can get continuity of the elements at the 6-way connector but not at the 4-way and no cont'y of the thermister at the 6-way. Theoretically it should all be wired in series for both elements to be protected I suppose.

Cheers again,

Steve S.

[NikpV]

Dear NikpV,

As I intimated, electronics is not my strong point! As far as I can remember the seat base has 4 wires going to it....2 go to the element, and two to the thermister.They lead back to a 6 way connector,the other two wires of which feed the backrest element (which has no seperate thermister of its own)It gets complex here ,I'll check in the morning, but there are connections to the relay,and then onward to the 4-way connection to the loom. You can get continuity of the elements at the 6-way connector but not at the 4-way and no cont'y of the thermister at the 6-way. Theoretically it should all be wired in series for both elements to be protected I suppose.

Cheers again,

Steve S.

 

 

ahh definitely sounds more like a thermo switch/thermistor than a thermal fuse - wonder if you went to a vw parts place whether they would have a replacement - any chance of a picture/any writing on it? I yu could work out a spec perhaps could source an equivalent. Will have a look on a well known tech info disc for the circuit when I get home

[mumof4]

Now..this is gonna sound daft....with heated seats......if the electrics got wet..is there not a chance of the seat becoming a bit lively?...(serious question)..just wondered...as to me...heated seats sound great..but just more chance of something going wrong..

[NikpV]

Now..this is gonna sound daft....with heated seats......if the electrics got wet..is there not a chance of the seat becoming a bit lively?...(serious question)..just wondered...as to me...heated seats sound great..but just more chance of something going wrong..

 

 

even if no insulation is there we are talking 12v - not high enough to produce a reaonable current through you even in exceptional favourable circumstances

[Smilge]

Now..this is gonna sound daft....with heated seats......if the electrics got wet..is there not a chance of the seat becoming a bit lively?...(serious question)..just wondered...as to me...heated seats sound great..but just more chance of something going wrong..

 

 

even if no insulation is there we are talking 12v - not high enough to produce a reaonable current through you even in exceptional favourable circumstances

 

Er what?!!! .... believe it or not 12V is a lethal voltage and a current of 500mA can kill you!!!!!

[Guest MATT jr]

...it would be one of those things i would have to check 5 times that its switched off really.

 

i have an image of driving down the motorway with my seat on fire.

 

MJR :D

[mumof4]

Now..this is gonna sound daft....with heated seats......if the electrics got wet..is there not a chance of the seat becoming a bit lively?...(serious question)..just wondered...as to me...heated seats sound great..but just more chance of something going wrong..

 

 

even if no insulation is there we are talking 12v - not high enough to produce a reaonable current through you even in exceptional favourable circumstances

 

Er what?!!! .... believe it or not 12V is a lethal voltage and a current of 500mA can kill you!!!!!

 

 

blimey....isnt 12v a bit high for heated seats?.....unless they vibrate aswell i assume.. :D

[Guest gooner52]

had heated seats in my scorpio ,change all the heated pads,was not a bad job to do..

 

took a while,it would seem they pack quite often on them,not sure about the galaxy

 

:D

[NikpV]

Now..this is gonna sound daft....with heated seats......if the electrics got wet..is there not a chance of the seat becoming a bit lively?...(serious question)..just wondered...as to me...heated seats sound great..but just more chance of something going wrong..

 

 

even if no insulation is there we are talking 12v - not high enough to produce a reaonable current through you even in exceptional favourable circumstances

 

Er what?!!! .... believe it or not 12V is a lethal voltage and a current of 500mA can kill you!!!!!

 

 

actually 20-30 mA can kill you although not in any circumstances involving a heated galaxy seat I can think of without being too sensationalist :D :D

[Guest gooner52]

will defo kill you a electric chair :D :D :D :D

[NikpV]

whilst being sensationalist (and off topic) 5cc of air can also kill you :D :D :D

[mumof4]

once again off topic......so can a heavy duty frying pan if enough force is exerted to swing it to connect with a certain part of the body.. :D

[NikpV]

once again off topic......so can a heavy duty frying pan if enough force is exerted to swing it to connect with a certain part of the body.. :D

 

 

less surprising though than the air or tiny currEnt :D :D

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(unless someone creeps up on you with it :D :D :D :D :D )

[mumof4]

very true....... :D

 

 

 

guess i wouldnt want to wet meself on a heated seat!...not that i ever do wet myself you understand.. :D :D :D

[Guest MATT jr]

took a while,it would seem they pack quite often on them

 

i heard they do if u have a big wallet! :D :D

 

...they do say not to have anything in your back pockets if you have heated seats.

 

MJR

[Guest gooner52]

very true....... :D

 

 

 

guess i wouldnt want to wet meself on a heated seat!...not that i ever do wet myself you understand.. :D :D :D

 

 

makes you wonder why when you buy the heated seat option, it comes with leckie sunroof

all that rain commin in straight on the heated seat.

 

shocking :D :D :D