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Monday 4 October 2021

Defender Puma heated seat electrics

We already had the Exmore Trim heated seat elements in the seats in Shelley's car. I wanted to wire them in using the original Land Rover switches.


It was easy to find a set of switches on ebay with the connectors. I'm not keen on them being pre-wired but that's how they came. Land Rover's standard wiring has the heating element controlled directly by the switch. I was unable to find out the current limit of the switches, nor the current draw of the Exmore Trim heating elements. All I know is that they use a 20A fuse for the pair.

It is safe to assumed, that the seats draw less than 10A per seat. I didn't want to take any chances with the Land Rover switches, so I have run them to relays.

The above is the updated circuit diagram with the heated seat switches connected via fuse 33. I also ran cables ready for a Sub-Woofer. The positive feed is shown in the above diagram, connected via fuse 32.


I was able to buy the contact pins that fit the standard Land Rover fuse boards, so I was able to use two of the spare ways in the under dash fusebox, to fit the fuse for the heated seat switch feed and another for the sub-woofer power. Both are switched from, what is called, the Window relay. That relay feeding various things, like electric windows and heated seats, when fitted, plus the windscreen wipers.

It's a bit tricky to access the fusebox because, although it can be unbolted, it does not fit through the opening in the dash. I managed to do what I needed.

I had a bit of luck with the feed for the power to the seats. There is an unused fuse in the under seat fusebox. Fuse 4. I happened to have the right spade connected to add in to the plug in that fusebox to connect to Fuse 4 and that fuse is marked as 20A. Perfect for my needs.


I ran a wire from the under bonnet ground stud to an unused stud under the seat. That probably wasn't necessary but with a definite negative connection to the under seat point, I was confident using that for all the negative connections.



I made up some harnesses and threaded them out in to the engine bay and under the car to the UK drivers side seat box. In that box are the two relays. They are attached to the relay brackets handily provided by Land Rover. From there another cable runs to the UK passenger side seat box.


It's just a job of terminating all the wires and plugging them together.

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