Power Seats Driving Me Insane

[honorforte]

I’ve only had my 88M5 for a few months but the seats are really unpredictable. The fuses are fine, the connections seem good, and the switches themselves are NOS and working great. Every button causes a click in the control unit under the seat, but the functions just come and go constantly. Sometimes one only moves back. Then it only moves forward. Each function comes and goes day to day, and some functions worked and then stopped and never came back for weeks now.

Today I moved my driver seat forward using a drill on the motor because only the reverse function is currently working. I put it a little too far forward and now the reverse action has stopped too…worst part is the square bit receiver on the end of the motor cracked as well, so now I can’t even manually move it backwards. It’s stuck.

Should I take the seats out and just try fixing them up, I don’t even know what to start diagnosing with because it’s all intermittent. At the moment I want to throw these seats away and order manual e30 sport seats with adapters because I literally can’t sit in my car right now. Just frustrated. I can’t even get to the front bolts to get these out because the seat is stuck in place.

Any advice? Is it insane to take m5 seats out for some manual e30 sport seats as a swap? I see the adapters being sold on here.

Thanks for your advice.

[kojo96]

I’ve only had my 88M5 for a few months but the seats are really unpredictable. The fuses are fine, the connections seem good, and the switches themselves are NOS and working great. Every button causes a click in the control unit under the seat, but the functions just come and go constantly. Sometimes one only moves back. Then it only moves forward. Each function comes and goes day to day, and some functions worked and then stopped and never came back for weeks now.

The control unit may have bad solder joints and you'll need to re solder them.

Today I moved my driver seat forward using a drill on the motor because only the reverse function is currently working. I put it a little too far forward and now the reverse action has stopped too…worst part is the square bit receiver on the end of the motor cracked as well, so now I can’t even manually move it backwards. It’s stuck.

This sucks, you have to use a very steady hand doing this and go SLOW!

Should I take the seats out and just try fixing them up, I don’t even know what to start diagnosing with because it’s all intermittent. At the moment I want to throw these seats away and order manual e30 sport seats with adapters because I literally can’t sit in my car right now. Just frustrated. I can’t even get to the front bolts to get these out because the seat is stuck in place.

Do a search, there's information on how to fix the seats.

Any advice? Is it insane to take m5 seats out for some manual e30 sport seats as a swap? I see the adapters being sold on here.

That shouldn't even be a consideration, at all. Fix what you have.

Thanks for your advice.

[Etip]

Well I can't help you, but can commiserate. Mine does the exact same thing!!!

I've taken them out. Tightened everything, sprayed contact cleaner on the relays, put it back together and...... Nothing changed.

If you figure it out, let me know.

[Mike W.]

OK, since the control unit clicks, that suggests it has power and the switch assy works. That's good, a big deal. First thing I would do is buy a used, hopefully working power seat control box and swap it out. I doubt they're expensive, they seem pretty reliable and they used them on a bunch of cars. (I think sport and regular are the same, and used on Es 23, 24 and 28) But swap out the control unit and that will either fix it or eliminate it if the same symptoms persist.

If it doesn't fix it, report back and we can go from there.