Heated seats

i have a 2002 mk 2.5. It seems to be a base model as there is no air con, manually operated mirrors, cloth seats etc. I have recently obtained a couple of leather seats. They are heated seats. Ive connected the sockets into the harness under both seats. I’ve seen various posts on other sites concerning adding heated seats to a base car that didn’t originally have them. No one seems to have a clear answer. I’ve had a look behind the blank next to the cigar lighter where the heated seats switches will be there seems to be no connector. My questions are, is the car pre wired at the factory to have heated seats retro fitted? Are there sockets fitted somewhere to allow the relays that control the heated seats to plug in? Or…will I have to start from scratch and wire the seats in myself

I had exactly the same issue when I had a Mk2.5 (also 2002 with no AC and cloth seats). It is possible that other variants of the Mk2.5 do have the complete wiring as several people assured me that it should be there!


On the car I had, the wiring & connectors for the heated seats existed from the seats to where the relays would be (top of the drivers footwell above the accelerator pedal) but no further. So to complete the upgrade would have required the relays, switches and wiring loom/connector from the relays to the switches. I never managed to source these items (except the switches) and drove around with unheated leather seats until I upgraded to the Mk3 (with heated seats as standard Laughing).


While I may be guilty of advising members that I thought the wiring should be there, after some fifty hours of research and some help from a gentleman in Holland who solved the problem (he had a Mk2.5 standard car, and a scrap M2.5 Sport (where heated seats originate) and was able to remove the missing link from the latter and transplant it into the former. This is a tricky operation, and requires the knowledge and ability to extract pins from the scrap car ‘dash loom’ main connector and reconnect it to the heated seat switches, which also came from the scrap car.
I sent a PM to each member who posted on the previous thread (five of them) and received only one reply from a local member, who told me he didn’t use the car at all in the winter, so wasn’t bothered about the seats not being heated. ccsdigital was one who I sent the PM to. - this is that PM.


New information now posted on the Mk2.5 thread, If you’ve forgotten where it is, it’s under technical/Body Repairs & styling. It may move to page 2, if you don’t access it soon.it will move to page 2. Last post is by Drumtochty, the main info is two posts before that.

Best regards,

Gerry Nicholls (Gerryn)

This is the original thread, presumably mention of cost put the rest off, so left me with the firm opinion that most members are cheapskates, and expect free info and material for nothing.

I still have three looms, but all put to one side in disgust quite frankly.

Eeeeek. This really does sound like more trouble than it is worth. It would’ve been nice if I had got the seats up and running, just to add a little when I come to sell it. If I come across a cheap switch with the plug fitted I might re visit the task. Many thanks for the replies. Regards. James

Put this in context, Heated seat Switches on Ebay can cost anywhere between £22 to £28 , and Relays (not always the correct one) are between £6 and £9 each. So total cost of spare parts from Ebay sources can be anywhere between £34 and £46. Cost of my loom, with all connectors supplied, plus instructions, is £12.50, with Crimp connector tool an extra £5.50 - these alone can cost twice that price from most other sources.

The price was cut to the bone, literally, to make it competitive. (Not enough apparently, as most appear  to see this as a rip-off.)

Re your post, you will NOT find a heated switch complete with a plug, - all switches come with a socket, (the switch is a plug in itself) and the socket invariably comes with original wiring cut off, as anyone removing the switch from a scrap car cannot be bothered to rescue the total wiring - with pins still attached.

Pins? - From square 1, all fitted and unfitted parts supplied on any NB dash are wired for any options, and terminate in a ‘common’ connector (Large white connector in the drivers footwell.) This consists of a terminal connector , which is clipped to the firewall, and terminated with female connectors. The matching male connector is also plugged into this already, and any optional connections are terminated with matching male ‘pins’ which have to be pushed into the male connector; otherwise there are blank holes where optional wiring  fits. Other than the dutch gentleman, I’m the only one who knows where these random positions are.

With help from other members, including Drumtochty, who has access to the Mazda parts list, it appears impossible to buy spare pins, otherwise the process would be a lot simpler, so added connectors are supplied to enable connection to the relay bases, as the only viable point where you can make the heated switch connections. So, a plug at the end of the heated switch loom wouldn’t do anyone any good, it’s the pins at the end of that loom which must be acquired.

Nobody selling stuff off a scrap NBFL Sport is going to bother extracting the loom pins from the donor car, - it’s too much aggro. - That’s why heated seat switches are sold with ‘cut off’ wiring. (full wiring may be cut off, excluding the necessary pins) My loom has matching wire colours to those fitted to heated seat switches, which makes the process of connecting the loom simpler, and as they are ‘official’ OEM colours, they will make anyone’s future fitting or maintenance problems simpler.

AS the alternative solution offered on Nutz, requires a complete re-wiring solution, including buying from Halfords or other sources - the necessary relays, relay bases or matching female connectors (in lieu of bases) plus base wiring- at Halfords who do not stock matching OEM colours, And suggested main connection is NOT as per official wiring diagrams, but in both cases (the ere two solutions) use either headlight wiring or somewhere else to get a feed from, it’s NOT- ‘per book’ and can also blow fuses if everything is used together. - Bearing in mind the most likely use of heated seats is at nightime, when it’s both dark and really cold!

All things considered, the fact that seat sockets and relay bases are part of the dash loom (with everything included) buyers of heated seats can mislead themselves into thinking they can just plug the seats in and they will work is a hopeful assumption that isn’t correct, when the seat heat switches, relays and the missing links are not provided somewhere., Both items can be bought off ebay, but not the missing loom. Hence, my intended loom, which apparently, no-one wishes to buy.

While some may consider it ‘petty’ - the heated seat switches come with two individual lamps, one for normal dash lighting (nightime) and the other lamp to indicate an ‘ON’ state, the NUTZ solution excludes the dash lighting altogether, while I include it.


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Infortunately it seems that the MK2.5 car does not have a generic wiring loom, so there are areas where certain cars are deficient not just in heated seat wiring but also in other areas such as remote door locking for example.

Gerry(Gerryn) has put a lot of effort into researching solutions for the heated seats where the car does not have the required loom facility. I would suggest that anyone who wants to upgrade a MK2.5 loom to facilitate heated seat wiring take his research/advice seriously. 

I am still hoping that he will take a similar interest in the MK2.5 remote as no-one to my knowledge has retro fitted this successfully even though only six wires involved.            

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