Electric seat moving control switches fix - pics & writeup

[BMWDriver]

Here are some pics of the switches box I took apart. Symptoms were: seat controls would move seat forward but not back, and headrest up but not down.

Tilting and raising seat were fine. After fiddling with the switches though, giving some angle or pressure - can't figure out which - the seat went back
and headrest down.

What gives? New switch box needed? Nope, the thing opens up I notice. Let's take that sucker apart.

First, remove the thing. Here it is. On the back of it, you can see illustrations on how to remove the box. Neat!



Step two, take the thing apart. Pry it gently open, and... OMG! Look at all the tiny parts that fall out of there! Lucky for me, I lost nothing. But how the hell am I gonna put it all back in?


I had to pick up the smallest springs with a paperclip I unbent, since I could not find my tweezers. A good ol' cent to give an idea on size. Twenty small springs, and five big ones, if you can say that's big. Five small "barbells", and five long ones. These are what make contact on the cutout PCB; they travel as you move the switch.


These things all have one or two large spring embedded in them. They all have to be fitted with them, so at least that's one less mystery in this switch box puzzle.


This is the reason why the switches ain't working proper. You can see the smudge, whatever it is, accumulated on it. Many of these barbells are dirty and blackened, and you can also see that the PCB is dirty as well with this stuff. I've never seen grease before on a PCB, but my experience with them is still limited; I would think that it's a conductive grease that allows electricity to pass through and also allow the parts to move easily. So I chose not to take it all off, but only scrape a bit with my screwdriver on the PCB where it's obvious the barbells moved, and wipe clean all the barbells themselves.


You can see many are dirty, though the camera's flash sort of makes it less obvious. One of them also looked arced (it was blackened).


So how do I put it all back together then? Well it turns out gravity is on my side. First I raise the top part of the box on a bottle and set it upside down so the switches can hold into place. Then the switches go in. Finding where they go exactly and which way was a bit of a challenge. I had to use the empirical method. The springs also make it a bit difficult, but you basically have to set the springs on them, compress them one way as you put the switch in - as in move the switch to a side - and then they just set in and stay put.

Then you can see where all the mini springs fit in. They all go underneath each barbell, in twos. Once I manage to put those super tiny springs in, I only needed to drop the barbells on top.


Then, I have a look to make sure I put the PCB part on top of it correctly. Unfortunately, it is not obvious how it goes into place. I get the impression it would close both ways. But after careful observation, I manage to lay it on correctly.


And, voilà, put the switch box back into place and all works as if brand spankin' new. That was fun. I tip my hat to the designers of the thing.

[tim eh?]

And I tip my hat to you for doing such a nice job and posting such a good writeup and not complaining about the switch I sold you.

[Bill R.]

Another view is this writeup i did a few years back on it

http://www.lehrmangroup.com/rickard/seatswitch.html

[leicesterboy15]

OMG that is brave! You must have the patients of a saint!

[BMWDriver]

Another view is this writeup i did a few years back on it

http://www.lehrmangroup.com/rickard/seatswitch.html

Wow, that's nice too! I'm not sure what happened that day, but I just went ahead and tested and fixed both seats. Took me the whole afternoon, about six hours for sure.

[BMWDriver]

And I tip my hat to you for doing such a nice job and posting such a good writeup and not complaining about the switch I sold you.

It was a very fun project Tim! I like saving things like that, makes me feel like some ecological hero who saves wastes

Can't wait to put my seats in, but I'm still undecided with the color scheme, because there are a lot of possibilities.