997 heated seat swap

Just wondering if anyone can help with an electrical issue I’m having with a seat swap from heated 996 to heated 997 seats. I’ve got the electric backrest working but I’ve reached the limit of my electrical knowledge when it comes to getting the heating elements in the 997 seats to work. I know the 996 seats have a relay in the base which allows low/high setting of the seat heating but the 997 seats don’t have this. Instead they use a switch inside the vehicle, my issue is how to wire up the seats to keep the OEM switches in the car. I’ve worked out (from another forum) that using the 996 seat loom and relay and connecting the output of that to the 997 heated elements should work but wanted to know if anyone had actually done this. Any advice gratefully accepted!

Thread 'The old 996 "seat swap" 997 challenge....and it's mysteries!' 14 Mar 2025 Hi, I am aware that this has been done/documented before but I never really found a 100% clear yes/no or how-to-install when it comes to fitment and installing more recent OEM seats in a 996. I am looking for a nice replacement for my current stock 996 Turbo "comfort" seats, which I find pretty uncomfortable on longer drives. Would like to be seated a little bit lower and the bolsters could be a little wider for my frame, so my back would be more IN the seat iso against the bolsters. My current seats (see below) have heating, memory and two electric buttons: one for up-down and front-back... NINENINESIX Replies: 26 Forum: Porsche 911 996 (1997-2005)

Thanks for the reply, I’ve seen this thread and it doesn’t cover the heated elements issue I’m having, the seats in the thread are non heated so it’s not that helpful for my particular issue.

M Thread 'Fitting 997 heated seats into 996... Swap for your 996 seats' 11 Mar 2014 Hi all, Following on from recommendations by many on here, I bought a set of 997 seats to replace my hardback sports seats. Fitting them physically was very simple, however the wiring connectors are different. After much discussion and trial and error (special thanks to pj_sibley for his personal tuition!!) I gave up and decided I'll get some 996 connectors and rewire the 997 seats. In order to do this properly though, I was hoping someone may have the wiring diagrams for both 997 and 996 heated seats? Would appreciate any help! Cheers :thumb: mazza Replies: 18 Forum: Porsche 911 996 (1997-2005)

Here is a bunch of stuff on this subject. I have 9x7 seats with heater elements in my 986 but have not really got to the bottom of it and i have been building this reference stuff for when the time comes! Keen to find a working solution! https://www.planet-9.com/threads/987-2-base-seat-to-14-way-memory-seat-conversion.255990/ https://www.dennisvogel.com/heatedseats/wiring.html Heated Seats video - and on Boxa - https://www.boxa.net/topic/84441-986-heated-seat-retrofit-how-to-video/#comment-1119394

Thanks for the info, I’ll have a look through it

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I was expecting there to be a simple relay based solution to make them work as I have seen on retrofit solutions, which is probably why I have the video. I can’t remember as I have not looked at this for over a year. Unless your car already has the relays, the genuine Porsche parts required are not the easiest to source.

Yes I’ve got the relays in the old seats, I’m just not sure 100% how to connect them into the wiring on the 997 seats, I believe terminals 8 and 13 on the 997 seat connector are for seat heating though. I just need to identify the output terminals on the old 996 relay and in theory it should work….

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Your comment here reminded me of something I hadn’t saved. Someone on Pistonheads has what you have and talks about how easy it is when you have all of the bits in front of you. I suspect that doesn’t apply for everyone but it should get you well on your way…hopefully.. He. Added some notes and a couple of pics for me Porsche 911 996.2 3.6 C2 - Page 7 - Readers' Cars - PistonHeads UK

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Thanks that’s very much appreciated, I don’t really want to butcher my old seats but might have to given the new relays are about £230 each. If I get them sorted I’ll post what I did with a picture or two.

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That's what I found out when looking at the parts. Relays and looms, plus switches were going to be a chunk of cash and I was not sure how I could get them to work. Looking forward to seeing where you end-up. Good luck