TD5 Heated Seat Diagnosis

Thought I would get around to trying to rectify the non-functioning leccy seats as the cold weather approaches.

I am a bit challenged when it comes to using the multimetre so could do with a few pointers...

The fuse is fine (the other finctions sharing the same fuse all work as well). The other thing is that both sides have failed.

Are the squab and seat back seperate elements or part of the same circuit (i.e a broken element in the seat would affect the squab etc)? Could it just be coincidence that both have gone together?

Can someone point me in the direction of the best place to check for continuity for each seat?

So many questions....

Thanks in advance!

Les.

Yes they are seperate elements and yes they are part of the same circuit, parallel not series. All the control kit and electrics are underneath the seat andl difficult without removing the seat.

That's not quite right Frosty....

The elements are in series, so a fault in either will cause both to stop heating up. (Just checked this in the electrical library part of RAVE)

You can get at the headers to check power is being supplied without taking the seats out from the rear of the seats - remove the leather-ette cover which is held on by velcro, and checking out the RAVE electrical section, find the correct connector. You can also check continuity of the two elements from the connectors.

On my td5, both heated seats were broken when I bought the car, faults were: Burnt out element in base of drivers seat (when you strip the seat down, a small section of wire appears burnt - I removed this and soldered the two ends back together, checked continuity-> jobs a good 'un.

Passenger seat: Element continuities were fine, but there was a break in the pigtail of wire that joins the squab to seat back elements together in series - replaced piece of wire -> fixed. Still a seat out job.

Most irritatingly, getting the seats out required angle grinding off the single retaining bolt that sits through the floorpan as the nut on the bottom had seized completely. Apart from that it wasn't so bad - it's good to have the heating back

David

Thats great information David, thank you.

David Pye said:

The elements are in series, so a fault in either will cause both to stop heating up. (Just checked this in the electrical library part of RAVE)

David

Click to expand...

Sorry David, i must disagree on that........they are in parallel(i mean the seat circuits)......check out better.....see a nice parallel connection from Header 0761 to Header 0708 >> C0761-12 to C0708-4 (LH seat circuit) and C0761-13 to C0708-5 (RH seat circuit)

Anyway mr. Lesworth....if both have failed same time u have to check somewhere before these points.....beginning from fuse 15 in the passenger compartmet fusebox and earth at C0708(beneath centre console)...see Connector views in RAVE

Any way they are both on the same circuit,

Perhaps I am not doing a very good job explaining what I mean....

Each seat consists of two series wired elements but both seats are connected in parallel.

David

Perhaps I am not doing a very good job explaining what I mean....

Each seat consists of two series wired elements but both seats are connected in parallel.

David

Thanks all. What I think I understand is the LH and RH seat circuits run parallel to each other, whereas the seat squab and seat base elements are on the same circuit so a failure of the seat base elemtn will affect the seat squab (and vice versa) for each seat.

In other words I either have a failure prior to where the feed spits to each seat heater switch (I think this unlikely as both seat heater switches illuminate still when pressed - bit I will check for current) or an element failure somewhere on both seats.

I have the Rave pdf and have spent the last hour reading through the appropraite section so this is strating to make sense.

As mentioned car electrics is not my strong point!

Thank again for helping me get all this in context.

Lesworth said:

As mentioned car electrics is not my strong point!

Click to expand...

Keep reading RAVE/Electrical library and it will be