Putting sport seats into 1990

[ahlem]

I looked at a couple old posts about replacing my comfort seats with sport seats. The passenger side was a no-brainer. The driver's side, however is giving me a good fight. I am attempting to eliminate the memory wiring and just use the adjustable functions as with the old seat. I'd like to rewire the new seat to plug into the old one' harness but am finding three circuits that are different. The seat heater on the new one seems to have a momentary type switch and the old one has a 3 position toggle. There are three wires from one of the connectors under the back panel on the new one vs. two on the old one and finally, there is a relay on the old one under the back panel and no corresponding relay on the new one. Could I trouble someone for a link to the seat wiring diagram for a 1990 535i and for a 1995(?) 540i. The 540 seats have power bolsters on the front and no power lumbar, I believe. I'd like to avoid killing the old seat as well.

[shogun]

here you have them all
E34 (1988 to 1995 5 Series) Wiring Diagrams (http://shark.armchair.mb.ca/~dave/BMW/e34/)

E34 (1988 to 1995 5 Series) Wiring Diagrams
1988 e34_88.pdf (10,476,973 bytes) e34_88.zip (8,451,206 bytes)
1989 e34_89.pdf (10,863,822 bytes) e34_89.zip (8,588,005 bytes)
1990 e34_90.pdf (14,676,816 bytes) e34_90.zip (11,295,570 bytes)
1991 e34_91.pdf (18,332,496 bytes) e34_91.zip (13,399,412 bytes)
1992 e34_92.pdf (15,153,055 bytes) e34_92.zip (11,963,569 bytes)
1993 e34_93.pdf (15,214,090 bytes) e34_93.zip (11,994,722 bytes)
1994 e34_94.pdf (15,860,270 bytes) e34_94.zip (12,448,814 bytes)
1995 e34_95.pdf (15,392,094 bytes) e34_95.zip (11,897,304 bytes)
let us know how you made that finally, maybe even with pics.

The newer type seat heater have the electronics below the switch, as far as I understand they have no relay (no need).

[ahlem]

Thank you very much. I'll let the forum know how this goes. I saved a pile of the gooey wiring harness tape to wrap the revised harness when I'm done.

[genphreak]

Thank you very much. I'll let the forum know how this goes. I saved a pile of the gooey wiring harness tape to wrap the revised harness when I'm done.

How did you go ahlem, did you figure out what was needed to get the drivers side sorted out? Was the difference limited to the heater and memory mirror circuits?

For the heater, was the relay on the old seat there to support the old toggle switch- and did you end up requiring a remote relay for the new seat or something llke that?

[ahlem]

I didn't want the memory circuit on the driver's side so I disconnected all the "encoders" from the outboard ends. I extracted the old wiring harness from the old seat. The passenger side was plug and play except for the bolster. The driver's side was a bit ominous at first but as I dissected out the memory circuit the rest was quite a bit simpler. I needed the car to stay functional so I got the seat pretty operational except for the bolster again. The inboard switches for the driver's seat still needs some work and the speedo cables have stretched in a couple places and will need the shortening fix. I already did the passenger's head rest but need to do a couple more there.

[genphreak]

ahhh... yes well its hard to get it all dead on first time in. Have a look at Shadetree's stuff (http://mysite.verizon.net/marcuscorbin/index.html), Marcus' incredible e34 upgrade guide has got a lot of good info about seat conversions and all the other super additions. Very detailed stuff about all the wiring required and what parts are needed- as well as instructions and great pics, etc.

From what I've seen of it, his guide is definitely one of the most incredible e32/e34 DIY documents for anyone with an e34.

[Ross]

The easiest way is to get the seat harness from your old seat. Ignoring the position sensors on the back of the memory seat motors, it all plugs in like it belongs there.
Alternately the wiring for the memory functions is a discrete harness but quite a bit of work to remove intact.

[genphreak]

The easiest way is to get the seat harness from your old seat. Ignoring the position sensors on the back of the memory seat motors, it all plugs in like it belongs there.
Alternately the wiring for the memory functions is a discrete harness but quite a bit of work to remove intact.Yep. Tell me about it.... on a 1987 535i e34 with memory seats. the harness went to each mirror, a relay in the engine bay fusebox possibly via to the Power Distribution Box under the rear seat. I ended up taking the whole harness out of the car. (Could barely lift it, LOL!)