Alrighty, so I decided to take on the task of fixing the heated seat elements. I took a bunch of pictures and will walk through how I did it so you can follow and hopefully save your self a bit of cash but most importantly stenghten that bond between you and machine that we all really care about. If anyone has questions you can PM me or post on here, I will do my best to get back to you but find that I don't get on here for days on end sometimes.

I will start by saying if you don't have practical experiance with fixing cars, soldering, and lots of patience then don't bother, spend the money for someone to just put in a new one. I think they are like $100 each so not too exspensive. I mainly did this because it was snowing and freezing rain and had nothing better to do after work.

You will want to check continuity of the seat padwhile the seat is in the car to make sure you need ot go through this prcoess. i fyou do have continuity obviously check other aspects of the system and also sit in the seat and see if you lose the connection, alot of heaters will be connected until the seat is sat in and wires are seperated.

The tools I needed:
-16mm socket, extension, ratchet (to remove seat)
-#20 torx either bit or screw driver, I like the screw driver cause it's easier to manage.
-hooks for grabbing things
-multi meter
-good battery for testing purposes (you could use your own from the car)
-hog ring pliers and atleast 50 hog rings
-soldering kit
-solder (you want thin guage)
-wire cutters (you want some with good leverage to break the old hog rings)

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY055.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY035.jpg

So to start off with you want to remove the seat from your car, I added a link to another seat DIY that includes seat removal. I will give you the cliff notes for removing the seat:
http://forums.bimmerforums.com/forum...seat+cable+fix
-get a E36 M3 (mine came with vadars)
-disconnect battery
-Open drivers or passengers door (which ever is the problem side)
-Move seat fully forward and unbolt the 2 bolts at the rear of the frame, 16mm.
-slide seat back
-remove bolt covers on front
-remove the nuts, again 16mm
-tilt the seat back to access the wire connectors under seat
-unplug connectors
-set seat sitting up and tilt the top of the seat out the door, then lift the bottom to follow, be carefull to not damage plastic trim around door frame.
-congradulations! you have done the easiest part!

Alright to get to the more intricate stuff....

-Set seat face down on a blanket or something to protect the leather from damage.

-On the seat bottom there are 2 clips close to the seat back, those will either need to be broken (mine would only break) or easily remove them to save the clip (good luck). Then remove the 2 #20 torx screws at the front 2 corners of the seat.

-The seat cushion will now be loose, be advised that the foam and leather may be suck to the plastic from age and never being moved so work it off carefully, don't pull hard at it cause you may tear material.

-Fold the bottom seat cushion forward over the leg support to access the hooks that hold the leather.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY008.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY041.jpg

-Pull the leather toward the center of the seat to slide off the clips, the idea here is to not tear around the little holes so it will hold just as strong and not develop tears later down the road.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY010.jpg

-After unclipping the leather and paying attention to the way pieces are folded over one another (refer to pictures if you forgot how they were during re-assembly) you will want to roll the edges over. Rolling it over allows the material to strech but also reduces the stress its put under so it will keep it from tearing.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY011.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY012.jpg

-Now you will want to work around the edges cutting the hog rings. I did the sides first then moved to the center, this was the best method I came up with for getting them off and on without risking damage. You may have to cut the same ring twice, I found that it felt like I cut it, but it was still connected.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY013.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY014.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY015.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY046.jpg

-Once you have got the leather unclipped to the point the heater will come out you can stop, no need to unclip the entire cover if your just going to fix/replace the heater.

-With heater out you can look for noticable burn marks on the foam pad of the seat and on the heater itself, these will give you a good indication of where to check for breaks. I found that on my rear pad the wires were schorched causing them to not pass current. I had to pull sections of the wire and jump them, basically I lost some of the space the heating element works for to make a good connection.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY047.jpg

-You now want to hook the multimeter up and check for continuity, if you have reached this step and do then you wasted alot of time and should have paid attention to checking the continuity before removing the seat from the car. If you did check and it had an open circuit and now has continuity you need ot move around the seat material while watching the meter to see if it breaks the circuit.

I found using a floresent light under the pad helps to see the wire patterns and can aid in finding a break but due to the material used ot insulate the wires it hard to see where a break is. I started by opening from the fleece side (up side) to access the connection points. Only cut where you need to. The materials are glued together so you can't just seperate the pad layers.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY026.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY028.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY030.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY050.jpg

Once you have the solder points exposed you can check to make sure the small wire is properly attached to the big wire. What I did was open 2 sides that only have the 2 ends of the small wire (on seat bottom) and used the mutlimeter to check continuity between the 2 points to verify that section has a good connection. Work your way around until you find a problem area, repair, then check continuity through the connector (testing the whole pad). I found I had multiple points that were issues so many repairs were needed to gain continuity between the 2 connector pins. One the seat back it is one long small wire that requires a little more intricate work to figure out where the breaks are but if you have got this far you will be able to figure it out.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY049.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY031.jpg

Once the repairs have been made make sure you protect the areas where the material was cut open. I used electrical tape since it was late and didn't have a drivers seat to go anywhere. I would assume this is going to work fine for the long haul.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY052.jpg

Now the real fun begins...

Attaching the leather back to the seat takes the most patience out of this process because you want to make sure everything lines up to reduce wrinkling.

To start you want to mock up the heater element on the first block your going to attach, this means tucking the corners down in the seat foam and makeing sure its flat and even lined up.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY016.jpg

To attach the hog rings I found using a hook to grab the bar in the foam to lift it up some to make the hog ring easier to put on the easiest way. You don't want to pull very hard on the bar mounted in the foam because the foam is the only thing holding it in place and will tear with that right amount of force.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY013.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY036.jpg

You want to work your way from the deepest part out going from left to right or right to left attaching the hog rings. After you have the centers moounted then you can go and attach the side rings. This is the easiest way of doing it, trust me!

Once you have a side section attached you want to push the leather material into the slot where the 2 bars meet to ensure the stiched edges dont have bulges and will look just like they were before removal.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY037.jpg
http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY038.jpg

You then want to make any adjustments to the alignment of the hog rings and leather in the center portion prior to rolling material over the edges so that everyhting is centered and siting flush in the many nice cracks of the foam pad.

Then you roll material back over basically reverse of taking them off, you then will want to rub leather to smooth surface even smacking it helps to give it the final little adjustments needed to ensure a smooth surface with out streches or wrinkles.

Attach leater material on back side of seats using same hooks overlapping in the same manner it was taken apart, piece trim pieces back togethe ron seat and double check for continuity before re-installing seat in car (this could be done sooner if you want but the idea is once it's all buttoned up it should not shift much where while you are still attaching leather it could cause it to move around).

Put seat back in car and enjoy the pleasures of eated seats all over again!


If anyone has questions or needs specific help please PM or post message in this thread and I will help as much as possible.


While I was in there I noticed the foam be degraded from getting in and out of the car, I used some adhesive foam for sealing truck caps or door seals at a house. I just put someover the exposed metal and fluffed the pad to make it as smooth as possible.

http://i428.photobucket.com/albums/qq6/joe91985/seatheaterDIY020.jpg

Hopefully that covers it guys, sorry for the mis spellings but my fingers are cold and I don't feel like spell checking today... maby I will update it later on.


*** Fiberglass cloth can be used as the "fire proof" material in the heater, from what I had seen when I had it apart it looks like that may be what was used. Just wanted to make sure the information is here for anyone wondering the same thing.

forgot to put working time in.... took bout 4 hours, alot of that was screwing around with the elements trying to find breaks. If I had to go back into it, I could ahve the elements say replaced with new ones in bout an hour. Obviously thats knowing what I'm doing now that I've been in there.

Yeah I put some one sided adhesive foam on the points it was wearing the most to save the leather from tearing open. I have a company in CA (GAHH) that makes seat covers and do a excellent job... despite what alot of others on the forum believe, but I plan on buying the front seat sets in the future and replacing them and the foam pads and all... just buying some time.

Do you happen to know a source that I could look up what materials to use to make a seat heater element? I wanna make a set for my rears. It's gonna have to be 8 squares that measure 14'' x 6''. So far everyone I find online has no sizes close to that and want about $75 per pad. From what I saw last night it's flame retardent cloth and wires? Works like a light bulb element I would say is the best relation to it. I tried doing some searches fo how to "build" one but no dice.

if anyone has problems viewing this, it can be found here as the original I wrote up Heated seat repair... done! DIY - Bimmerforums - The Ultimate BMW Forum

Damn, nice HOWTO! Thanks for posting.

Good how-to! You could also use this to re-upholster the seats or combin with the carbon-fiber howto and overlay the plastic back!

thanks, dunno if anyone else is having the problem but I'm getting the x on the images. I linked them to my photobucket use copy and paste. If anyone has problems viewing them let me know.