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RX8 Passenger Seat Heater Wiring - Mystery Brown Wires!?


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I joined this forum a few years ago but haven't posted previously as after owning several old 110s before getting to my perfect 110 (courtesy of a large bank loan) it went from tank solid to swiss cheese in 10 months, it took a few years to get my enthusiasm back (and pay off the loan). Anyway Hi, I'm back in the game with a 110 CSW, overland ready..ish and a galvanised chassis.

If it's not too cheeky to ask a question straight off, I'd appreciate some help. There are loads of posts here and elsewhere on wiring up RX8 seats into a defender and all focus on the complicated drivers seat, saying the passenger seat heat element is simply Red +ve (via relay & switch)/Black -ve ..... off you go.

The trouble is, on the passenger seat base I have a brown wire running alongside the Red and another brown wire alongside the black. I've tried ignoring them and just wired the Red/Black but noo success so they are obviously relevant. Any ideas of what I should be doing with them to get the heated seats working would be appreciated? Pic shows what I've got. Thanks.


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Once you are adept with the meter, then the only addition I would make is that with auto electrics you need to reference the voltage back to earth and or battery. I have worked with a guy who was adamant that had the opposite voltage to the actual voltage as he had the leads the wrong way around.

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Seat heaters are often wired in series with a switch, such that if nobody is sitting in the seat, it does not get warm. 

Some of them have separate heaters for warm & hot.

In your case, I would bet on the latter.  I would try connecting say Red & Brown from one branch, via a fuse (maybe 20A) to a battery & see if the seat gets hot.  The fuse is there just in case they connect to the switch - and it's a dead short when you sit on the seat.

If one pair makes it hot & the other blows the fuse when you sit down, that's a switch.  If they both make the seat get hot, they will be two levels of hotness.


This puts me in mind of a thread I followed on another forum where someone was putting a Ford Seat in his truck - and was asking what all the mystery wires did.  In particular the Yellow ones.  People were suggesting just to connect 12V to the wires to see which combination made the seat hot.  Knowing a little about automotive wiring, I knew exactly what yellow wires / yellow sheathed wires tend to be 😉 - so I continued reading to see what happened!

Further down the page, he had discovered that the yellow wires (as suspected) connect to the side impact air bags - and they had completely obliterated the seat when they detonated.  I must admit, I chuckled to myself a little!

  • Haha 2
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Thanks for taking the trouble to reply. Long term, I agree, I need to put the time in a learn.

But with a full time job, the Mrs asking why I've spent the last 3 weekends alternating between the driveway and watching YouTube posts on seats, rather than doing all the stuff around the house that is "more important than the bl00*y land rover" and the kids waiting to ride in it, I was hoping for a bit more than a general consensus of ...'work it out for yourself'

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