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Discussion Starter #1
I know BMW's of our vintage aren't known for the best electrical systems. My E36 M3 and E39 540i had their qwerks, but what I'm experiencing now is a whole other ballgame.

The first issue started a few weeks ago, around when the temperature out here really took a dive (from around the 60's to now being in the 20's-30's, low 40's on a "warm" day). I don't know if the issues were onset by the cold but there seemed to have been a correlation.

Started with every once in a while, the radio wouldn't go on when I started the car, restart and it'd be fine. The sometimes the window switches wouldn't work, press the button a few more times and then the window would finally role up. Then the heated seats wouldn't go on the first time you pressed the button. Now my radio won't go on at all (for a while on the screen the DSP option was just greyed out- now it's not even there), the heated seats won't go on, the horn doesn't work (windows do work and THANK GOD the Sport button works.)

It sounds like a ground issue with a possible combination of a blown fuse. I know people out there have experienced similar troubles, but the progression is what's really puzzling me.
 

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I'm thinking ignition switch. They've been known to cause all sorts of electrical problems that would seem in no way related to the ignition switch.
 

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I can't see any connection between those components but I'm wondering about water ingress. I remember a thread about the horn and some other stuff not working because of water coming though the firewall. The interior can absorb a lot of water before it becomes obvious.

Do you have access to INPA? It's quite good for troubleshooting this type of thing.
 

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Discussion Starter #4
Never heard od INPA but I will look into it.
I just need some decent weather where I can really start to tear apart the car and look for anything that sticks out. I agree it's probably moisture/corrosion connected, hope it's nothing as serious as needing a new ECU/OBC

Thanks!
 

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Never heard od INPA but I will look into it.
I just need some decent weather where I can really start to tear apart the car and look for anything that sticks out. I agree it's probably moisture/corrosion connected, hope it's nothing as serious as needing a new ECU/OBC

Thanks!
Get a couple of buckets of Damp Rid and put them in the car. It will help absorb moisture inside the car. Cheap, and no harm if it doesn't help.

Regards,
Jerry
 

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Never heard od INPA but I will look into it.
I just need some decent weather where I can really start to tear apart the car and look for anything that sticks out. I agree it's probably moisture/corrosion connected, hope it's nothing as serious as needing a new ECU/OBC

Thanks!
INPA is original BMW diagnostic software designed to troubleshoot this kind of problem.

It's not the ECU. It doesn't control the stuff you are having problems with.
 

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Water ingress past the tail light seals can cause issues with the DSP amp, the radio and sometimes the Navigation system. That has been my experience at least. There are some electrical components under the front passenger carpet. Maybe inspect the carpet closely to see if it shows signs of having been wetted.
 

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ignition swith
 
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the reason i state this is because its a few modules acting up
 

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Good point. (And also suggested by x5alpine above.) All of that stuff gets some power from one of the 5 sets of contact in the switch, which may have gone bad, although I would have expected other stuff to act up as well.

From what I've seen on here, it's a cheap and easy fix to try.
 

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Discussion Starter #13
So an update...

Started having more glitches. Steering wheel would raise up when the visor mirrors opened, DSC light come on, a few other things.
Called my indy back home (Bill at Motorspeed West in Santa Clara- BEST BMW MECHANIC EVAR)
Didn't even get a chance to finish describing all the glitches and he cuts in "it's your ignition switch." He confirmed the year and then said they see it frequently, and that I need to replace the actual switch itself, not the lock, and that it's fairly simple and should cost me around $40.

Whew.
 

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Discussion Starter #14
Problem solved. Was definitely the ignition switch (Bill really knows his stuff)

Bit of advice for anyone who does the repair themselves, getting to the back torx nut was a pain, the only way to really do it is take both the lower and upper plastic covers off the column (in a youtube video I watched they only took the lower off.)
Other than that, pretty simple install, maybe a half hour total. All you need is a philips and flathead screwdriver, and T30 torx bit (I ended up putting it in a 1/4" 1/4"-drive socket and ratcheted it in. Even with both column covers removed it's still a tight fit.)
 

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Thanks for the follow up. It is good to get the resolution to threads like this.

To avoid STDs in the future, don't let you M5 play with those trashy E55s. They are bad news.
 
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