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Discussion Starter · #1 · (Edited)
I'll preface this by saying that for the low cost of a new OE part, I would just replace it and be on your way. But for the curious, the handy or the type that just likes to take things apart, read on. Common sense disclaimer applies: If you choose to follow this guide, please do so at your own risk.

The Ignition Switch (61326901961) as used on the E39, E46, E53, E83, E85 and E86 is known to cause wonky k-bus issues when the unit gets older and develops intermittent contact.

I won't go into getting to the switch. It's pretty easy and some good guides already out there.

Dis-assembly:

You can see how the switch comes together and all you need is a small screwdriver to take it apart. Start by removing the top cover. The front part will come off easily after that. When you get it apart some pieces may fall off, but I'll detail how to put it back together below.



You'll see it's just a cam and contact points, no ICs or anything more sophisticated than early 1900s electronics.





In the photo above you'll see the top right contact has a lot of "dust". This is the one that makes contact when turning the key to start the car. If this contact gets contaminated enough, I can see how some have experienced turning the key and nothing happens.

Cleaning:

You may be able to get away with just using brake cleaner. The switch body (not the cam itself!) is PA66 and very resilient to harsh chemicals, similar to other plastics in the engine bay. I personally took it a bit further and raided my wife's (fine grit) emery boards. Trim it with a blade so it's narrow enough to fit, then start working it up and down.

Don't go nuts. Don't let your OCD get the better of you and wear down the contact points to nothing. Remember, you're just cleaning it.





Trim your emery board as needed to get a fresh friction surface.



You'll see dust generated from both the contact points and the emery board after you clean it. When you're done, make sure you use brake cleaner to wash it all off.



After spraying it down, I used plain cardboard (such as the one behind a notepad) to clean in between the contacts themselves. Then i sprayed it again, then used the cardboard again. At one point I used a cardboard soaked in brake cleaner too. I wanted to make sure the contact points were as clean as possible.



Re-assembly:

Note the orientation of the one-start-per-cycle ignition lock (crescent-shaped piece). There really is no other way to put it in that makes sense. This is the part that most likely fell out when you took the unit apart.



Greased and ready for assembly. There's grease under that loose crescent-shaped part too. These are the factory grease points - I did not find grease anywhere else on the unit when I first took it apart. (Note : If you follow the guide you won't get grease on the contacts. The greased parts are only in the front, in a separate chamber from the contact points. I experimented with keeping it dry but it was noticeably grittier when turning the key. This note/edit is after 3+ years with no issues, and it's nice to have a smooth-turning key.)

Don't worry about the black piece that has the ball-detent, lock-detent and start-return spring. It is one captive unit.



This is how the two case halves snap together with the cam inside it. Cam is positioned for ease of assembly.



After assembly you then have to re-orient the cam so the front cover just slides in, and so the tab on the cam is behind the start-return spring.



Alternate view - Note how the cover is positioned relative to the cam ball and spring. The tab on the cam must be behind the spring to return it from the start position. Don't worry. This will all make sense when it's in your hands. Below is the cam in ON (not start) position.



All buttoned up. Use a table top, driving the switch body on it. This ensures the cover is installed straight on.

<img src="https://c1.staticflickr.com/8/7433/11535821604_90288d60c6_c.jpg" width="600" height="800" alt="Untitled">

On installation, you'll have to work the key to make sure the "splines" match where it goes into the ignition switch. Don't re-orient the cam itself using a screwdriver - you can damage the plastic. The battery should still be disconnected from when you first took it apart.



In the car.



The switch works, but as the ignition switch issue was intermittent to begin with, any proof in this "repair" will have to be long term.

Have fun, and an easy project if you have a spare morning.

Some more shots not necessary for cleaning. Sorry for the blurry pictures:

Key OUT position, all contacts pushed away.



Key in ACCESSORIES position, all but pin 2 (middle, below) are pushed away.



Key in ON position, only pin 8 (right, top) is pushed away.



Key in START position, all pins make contact.



Merry Christmas and a Happy New Year!
 

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Beautifully, meticulously, and comprehensively done. Excellent pics to demonstrate what this is all about..

I will add one bit of info. I used to commercially recondition and maintain electrical equipment with high quality contacts such as you have worked with here. Many are silver plated contacts to make good electrical contact, but more importantly prevent any corrosion that would create a high resistance connection. Best to not use anything as abrasive as emery because it removes the silver plate and prevents the contacts from staying healthy. They will never be serviceable again, and would have to be replaced.
 

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Discussion Starter · #3 ·
Thanks Stinger9. You're right, I did try to see as close as my naked eye could manage if the contacts did indeed have some kind of plating. The outboard contacts did seem to have a silver plating while the inboard contacts did not. I can't be sure though unless I take it apart. In retrospect a strong cleaner like brake cleaner + cardboard that I mentioned in the thread would have been enough, like you said. I guess my OCD did get the better of me after all.

To add I don't recall anything else in that entire mechanism that would wear and cause the intermittent contact. Whatever method you use to clean the contact without killing it would be helpful and is the only servicing that needed to be done. From taking it apart initially there was so much "dust", probably from the contacts jumping current thousands of times, vaporizing a bit if the contact material every time.

Beautifully, meticulously, and comprehensively done. Excellent pics to demonstrate what this is all about..

I will add one bit of info. I used to commercially recondition and maintain electrical equipment with high quality contacts such as you have worked with here. Many are silver plated contacts to make good electrical contact, but more importantly prevent any corrosion that would create a high resistance connection. Best to not use anything as abrasive as emery because it removes the silver plate and prevents the contacts from staying healthy. They will never be serviceable again, and would have to be replaced.
 

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We used to use a special metallic strip made just for this purpose. My company used to supply them to us and I never paid attention at the time.
But I searched and found what I used to use. Strips are held in a pen-like device. Take a look:
http://www.mcmaster.com/#electrical-contact-abrasive-cleaners/=pyec21

And here is something else for you to get an idea of what you're trying to accomplish:
http://www.dxengineering.com/search/product-line/vibroplex-contact-cleaners

And see the attached sheet for another similar product.
 

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Discussion Starter · #5 ·
We used to use a special metallic strip made just for this purpose. My company used to supply them to us and I never paid attention at the time.
But I searched and found what I used to use. Strips are held in a pen-like device. Take a look:
http://www.mcmaster.com/#electrical-contact-abrasive-cleaners/=pyec21

And here is something else for you to get an idea of what you're trying to accomplish:
http://www.dxengineering.com/search/product-line/vibroplex-contact-cleaners

And see the attached sheet for another similar product.
Thanks for the links. That's a good resource for those who want to give this a try.
 

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My car won't crank, no start when it has warmed up. Once it willing to start, it starts like normal.

Could it be the ignition switch? My car does not show any sign of electrical gremlin around(I know how it does because I replaced the ignition switch once by garage)

Merry Christmas
 

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Great pictures! I've never seen the insides of the switch.


My car won't crank, no start when it has warmed up. Once it willing to start, it starts like normal.
Check for power at the starter when the engine doesn't start.
If there is power you have a bad starter, if there is none, it's the switch.

Read the No Start thread in my signature for more info.
 

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Starter was replaced with a brand new Bosch still the same. Read your thread but one thing not quite understand about EWS. You said that if neither of the keys can start the car, it probably not the EWS. If both keys can not start the car, isn't the EWS be the candidate to look at?

Thanks for sharing.
 

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Trying both keys would rule out a key problem, because little chance both go bad at the same time.
If there is an issue with the EWS module, then yes neither keys would work.

Is there power at the starter?
If there isn't, trouble shoot the ignition switch. This thread should help with that.

If the switch checks out, then scan with a BMW specific scanner to detect EWS faults.
 

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Discussion Starter · #11 ·
Excellent work and incredible detail.
Thanks Jake. Based on Stinger9's input I've looked into contact cleaners specific to silver-plated contacts and it looks like a product called DeoxIT is the one to use.

This is a link to Amazon for the product. 187 5-star reviews so far with success using it in switches, amps, guitars, medical equipement and everything in between. For $14 it's worth having around the house and definitely worth a try on the ignition switch. Especially since getting it out of the steering column is easy.
 

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To burnish the contacts, cut a small piece from a US Dollar bill and drag it between the contacts. Mechanics have been using this trick for nearly 100 years. The currency paper will shine the contacts right up.


Sent from BimmerApp mobile app
 

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Bmw 320i 2002 ignition sw fix

HI,
cvx5832 YOU ARE RIGHT ...I DID FOLLOW YOUR INSTRUCTIONS AND NOW BOTH KEYS WORK AND NO MORE STARTING PROBLEMS.
I WILL LET YOU KNOW FOX... THAT FOR ME IT WAS ALMOST HALF A YEAR HAVING STARTING PROBLEMS...UNTIL MY ENGINE DIED ON TRAFIC AT THE STOP LIGHT.
AT THAT TIME I DID SEARCH THE INTERNET AND FOUND cvx5832 THIS POST.
cvx5832 THANK YOU AGAIN FOR A BEST EXPLAINED PROCEDURE.
THANK YOU AGAIN.

http://forum.e46fanatics.com/newreply.php?do=postreply&t=1018686
 

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Thanks for an excellent write up.

I've just finished mine. The ignition contact did look a little dusty. My car has done 160k miles for reference.

On the cleaning side of things i used a magneto file. It is a very fine sort of needle file to gently clean the contacts and then i used Servisol Super 10 contact cleaner on all the contacts.

A while later i remembered i had some Electrolube contact cleaner / lubricant so i blasted the contacts with that too. Probably over the top but i already had all this stuff laying about.


I was wondering if using some pliers to tweak the spring pressure on the ignition contacts might help.
 

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Another approach is to pick up a used ignition from a yard for $5, and swap in one of the non-ignition contacts. Still worth cleaning the inboard side, but it is an easy way to get a clean contact without wearing off the plating. All of the contacts are identical, but the ignition contact has more arc-ing and wear.
 

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Start by removing the top cover. The front part will come off easily after that.
Note: his front is my top; and his top is my right side cover. The following is based on this new orientation.
His instruction is not quite right, as the round top cover should be removed first before the curve side cover. Notice the OP installed the top cover last, so why he did not remove it first is the mystery. The risk of remove the right side cover first is the small locking tabs on the top cover could be broken. I point them out in the pictures with red arrows:
Camera Digital camera Reflex camera Camera lens Point-and-shoot camera


Clearly in pic below, if the right side cover is forced out then it will damage the 2 small lock tabs on the top cover:
Automotive tire Tread Camera accessory Camera lens Carbon



How to remove the steering column cover:

Hope these help the next brave guys.
 
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