Retrofit Heating Element Into Seats - 540i

[absolutezero273]

Forgive the noob question but I searched all I could and only came up with one mention of adding heated seats to a e34 540i. I know I've got plenty of work to do but thinking of this in the winter.

This thread (that I'm not allowed to post the URL because my account here is too new: "Did 540's W/O Heated Seats Come Wired For?") mentions that the wiring is there to the seats. But I can't find any discussion of actually adding the factory/oem or aftermarket heating elements to the seats and wiring the switch.

I just installed aftermarket heating elements in my wife's Ford Windstar over Christmas break so I have a general idea of what is involved. But on the e34 how difficult is it to remove the skins?

Is that because it is nearly impossible to do this?

I will always search before asking but I may end up asking some fairly basic questions as these e34s are new to me.

[bubba966]

You might have to add the wiring harness for the heaters. But the wiring to the seat for that harness is already in the car. If you have power adjustable lumbar support then you already have the seat heating wiring harness in the seat as the lumbar shares the wiring harness with the seat heating.

Taking the skins off the seat should be easy with a good set of hog ring pliers.

So you would need the heating elements, switches, and possibly the wiring harness in the seats to do it. There was a factory retrofit kit that they used to make but is NLA now. So it wasn't "nearly impossible" to do as they were doing it at the dealer.

The thing is that seats that came from the factory with heat had the heating elements sewn to the leather. So I'm not sure how the retrofit heating elements differ in feel or heat compared to the factory elements. As you already found out there's virtually zero info on this as people usually just swap seats to get heat.

I need to do this to my M-Sport which is how I know what I do. It was a Southern ordered car so they didn't bother optioning the heated seats... :mad Anyway, someday I'll find out how to use hog ring pliers. As my seats are far too nice to just swap out with some other ones that have heat.

[Aradaiel]

You just need to change seat leathers. I wrote a thread up for an e39, but the e34 is pretty simmilar. This is for aftermarket heater elements. You'd just need to change the leather itself and add the switch if you wanted factory stuff.

http://forums.bimmerforums.com/forum/showthread.php?t=1916996

[gixxerboy63]

Try this retrofit guide;
http://mysite.verizon.net/marcuscorbin/E34_Factory_Options_Guide.pdf

scroll down to page 123. It gives instructions on how to accomplish the install and gives part numbers.

[absolutezero273]

Thanks everyone for your help! Very much appreciated! I think I may do this while I'm tackling the twisted seat problem.

I'd prefer the factory parts but some of those, like the switch and wiring, look prohibitively expensive. Especially when an aftermarket solution, per seat, comes in at $100 for both base and back heat elements, switch and relay. Maybe I'll find used oem switches and mate that to the aftermarket setup.

[shaytanabyad]

Take pics and do a write-up if possible. It'll help the next guy with this...

[gixxerboy63]

Thanks everyone for your help! Very much appreciated! I think I may do this while I'm tackling the twisted seat problem.

I'd prefer the factory parts but some of those, like the switch and wiring, look prohibitively expensive. Especially when an aftermarket solution, per seat, comes in at $100 for both base and back heat elements, switch and relay. Maybe I'll find used oem switches and mate that to the aftermarket setup.

I am going to accomplish this mod when I have my front seats redone (very soon). I have already sourced the wiring harness out of a parts car along with the switches... however the switches didn't meet my visual specification (apparantly years of spilt Coke and other caked on crud), so I found a brand new pair on Ebay for cheap. Now all I need is the heaters themselves.
:cool

[jehu]

Do the elements ever break? Only my back support is heating ... the bottom is not... is it possible the element is damaged or would it be a wire/connector problem?

[KBHumphrey]

Do the elements ever break? Only my back support is heating ... the bottom is not... is it possible the element is damaged or would it be a wire/connector problem?
Of the four E34s I've owned, three of them had the same problem. Never really looked into it but I too am curious on the root cause of this.

[Aradaiel]

Might be unplugged, they have a y harness from the body harness to the seat. The back and bottom sections have seperate power plugs.

The most common failures of the seatheaters are hotspots due to cracking/resistance in the seatmat.

[Black 535i]

I have mine break in my car this winter and it has created a little hotspot under my left leg. Quite a shock in the back of the leg when it does heat up so yes they do break after years of work.

[Elekta]

They are sewn into the seat bottoms and backs, so if you are recovering these areas, then it's worth it. I know Volvo sells swap in heating elements, but the difficulty is in cutting out the old fabric and replacing it with the new one that has the element in it. Not sure if I'd recommend just placing a heating element under the existing fabric behind the leather. My parts car for the touring trailer project had heated seats and I cut out the bottom and seat back, but as it's sewn into the leather, I passed on the swap. I think new elements would best for the money/labor spent on the retro fit. As I have Nappa Blue leather, my chances of matching it with new leather are slim, but if you are black, grey or tan, you may fare better. I will take a pic of my skins and post them here so you can see what I'm talking about.

Not as easy as it looks. A decent leather upholsterer is what you need