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Discussion Starter #1
Hi all - I looked at several different posts and didn't see any quite like what I'm experiencing, so here goes - I got caught in VERY heavy rain downpour for about 5-7 minutes a couple of nights ago (I usually don't drive the beast - 2000 black on black E39 M5 - in the rain if I can avoid it), and after getting home into the garage and turning the beast off, weird electrical things started happening - brake lights went briefly on and off by themselves for 5 min or so, and the car wouldn't go to "sleep" - the instrument cluster "control section", odometer, tripometer and outside temp all stay on/lit, as well as the NAV/OBC screen (I can still manually turn off the NAV/OBC screen, which I did). I am also able to turn on and play the stereo - it's as if it thinks the key is in position 1, but the key is out of the car. Also, upon opening the door to get out of the car, there's a warning for a couple seconds that the key is in the ignition, which it isn't. I cannot lock/arm the car with the key fob, since it's in this strange condition. I figured this condition would eventually kill my battery, and sure enough it did after the 2nd night. I jump started the car this morning, drove it for 20 mins (still runs like a healthy beast BTW!) and the battery got charged back up. Now when I get home, I disconnect the negative wire from the battery so it won't drain (losing all saved settings and everything gets reset - grrrrr), and I am able to re-connect it and start it and go, but I definitely don't want to make a habit of doing that!!! So, any ideas what in the world is going on??? Did something get wet and now is forever going to be "ON"? I hate having an injured beast!!! Thanks for any suggestions you might have - I know there's are LOTS of knowledgeable folks in this forum and I really appreciate having such a great resource!!!
 

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Hi all - I looked at several different posts and didn't see any quite like what I'm experiencing, so here goes - I got caught in VERY heavy rain downpour for about 5-7 minutes a couple of nights ago (I usually don't drive the beast - 2000 black on black E39 M5 - in the rain if I can avoid it), and after getting home into the garage and turning the beast off, weird electrical things started happening - brake lights went briefly on and off by themselves for 5 min or so, and the car wouldn't go to "sleep" - the instrument cluster "control section", odometer, tripometer and outside temp all stay on/lit, as well as the NAV/OBC screen (I can still manually turn off the NAV/OBC screen, which I did). I am also able to turn on and play the stereo - it's as if it thinks the key is in position 1, but the key is out of the car. Also, upon opening the door to get out of the car, there's a warning for a couple seconds that the key is in the ignition, which it isn't. I cannot lock/arm the car with the key fob, since it's in this strange condition. I figured this condition would eventually kill my battery, and sure enough it did after the 2nd night. I jump started the car this morning, drove it for 20 mins (still runs like a healthy beast BTW!) and the battery got charged back up. Now when I get home, I disconnect the negative wire from the battery so it won't drain (losing all saved settings and everything gets reset - grrrrr), and I am able to re-connect it and start it and go, but I definitely don't want to make a habit of doing that!!! So, any ideas what in the world is going on??? Did something get wet and now is forever going to be "ON"? I hate having an injured beast!!! Thanks for any suggestions you might have - I know there's are LOTS of knowledgeable folks in this forum and I really appreciate having such a great resource!!!
Sounds like a short somewhere from moisture getting in where it does not belong. You might look for any lingering moisture in the engine bay (computer under right side air box) or even under the dash inside the cabin.

There should be some old threads discussing how to pull fuses and check systems. It may take a little time because you have to let the car "go to sleep" which can take up to 30 minutes (from memory) so you can then see which systems are powered up and how much electrical draw they are pulling. If the car won't go to sleep, then start with whatever system tells the car to sleep.

Regards,
Jerry
 

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Hi there. Nice to see another beast owner in the WNY area!

I would start by pulling the passenger cabin air box and then removing the white box cover to reveal the computer and some wiring, and look for signs of moisture. Another quick check would be to open the two side access panels in the trunk which reveal the CD player on the drivers side, and a fuse panel on the other. Look for water in these areas as well.

P.S. - Send me a PM if you need further help performing any work or diagnostics. I am also in WNY and happy to help if I can. There are a few of us that get together from time to time to talk about our cars and go for a cruise followed by food, etc. Let me know if you're interested in meeting up! Also, do you have non-stock wheels on your car? If so I may have seen you driving last week. Not too many black E39 M5's in the area.
 
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Discussion Starter #6
Thanks for the good suggestions all - I looked under the passenger cabin airbox, inside the white box with electrical in it and did not see signs of moisture, only a small amount of dust, so that looks pretty good there. I was glad to see that white box appears to be sealed up quite well. The night it happened, very soon after it happened, I looked in the trunk, both sides, and didn't see water in there either. I used to get some water in there, both sides, until I fixed my tail light gaskets, thanks to the great info in this forum. I also took the panels off around the steering column and down by the pedals, and couldn't find any water/moisture there either. Also looked at the fuse area in the glove box, no evidence of water/moisture there either. Is there something that controls the position 1 functions that could have permanently shorted "on"? I should have mentioned that, the day after, after I drove the car around a bit, the car actually went all the way off for a minute, to the point where I could use the fob to lock/arm the car, but then the alarm went off and I could see that the car thought it was back in what I'm calling position 1. I turned the ignition to position 2 and back, and saw the lights that now remain on, would flicker a little, and on occasion go off, so I was thinking maybe some moisture was slowly drying out, but to my dismay, I found after a 2nd drive, the flickering has stopped, and the car just stays in position 1 (no more flicking, dashing my hopes that it seemed like it was slowly improving). Ugh...
Tim - yes, I have AC Schnitzer 5-spoke black chromed wheels with my warm weather tires on them, so very good chance it was me you saw. My winter tires are on my standard M5 wheels, which I just changed out 2-3 weeks ago. I think it would be great to get together at some point - please let me know when a gathering is scheduled. Thanks!
 

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Discussion Starter #7
Wow, well guess what? Inexplicably, it just started working again perfectly. I put my craftsman battery charger/tender on it right after a 30-45 min drive, and it still shows charging (solid amber light on the charger) after about 3.5 hours - all instrument cluster lights are off and the car is in sleep mode! Previously after about 15-20 mins, the charger would stop charging and show trouble with a solid red light. It did this probably 4 or 5 times that I tried it over the last few days. I can again lock/arm the car with the key fob, and it all seems back to 100% normal. I am thankful for this of course, but at the same time very puzzled! Is it possible my battery took some weird hit from the electrical gremlins brought on by the downpour, and now has somehow recovered?? Does the system computer do a periodic reset and perhaps that cleared the issue?? Again, very thankful, but also very baffled. So glad to have my beast back to 100%!!! Fingers crossed it will last!!!
 

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Discussion Starter #8
Had the battery tested this morning, and it checked out good - 12.66v while sitting with trunk open and 959 CCA. When I run OBC test #9 it shows 13.8v most of the time when the car is running, so that all seems good, right? I'm just happy, although mysterious, the full beast is back! :tonquesmilie:
 

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Had the battery tested this morning, and it checked out good - 12.66v while sitting with trunk open and 959 CCA. When I run OBC test #9 it shows 13.8v most of the time when the car is running, so that all seems good, right? I'm just happy, although mysterious, the full beast is back! :tonquesmilie:
Interesting. Something must have gotten wet and is now dried out. Hopefully it doesn't come back!

Glad you checked out the battery.

P.S. - tomorrow there is an autocross event at Ralph Wilson Stadium and a bunch of BMW's will be meeting there to get together and probably watch some of the racing as well. I don't know what time and I'm not sure I can make it, but wanted to put it out there. Send me a PM if you want.
 

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Discussion Starter #10
Interesting. Something must have gotten wet and is now dried out. Hopefully it doesn't come back!

Glad you checked out the battery.

P.S. - tomorrow there is an autocross event at Ralph Wilson Stadium and a bunch of BMW's will be meeting there to get together and probably watch some of the racing as well. I don't know what time and I'm not sure I can make it, but wanted to put it out there. Send me a PM if you want.
Guess so - I've got my fingers crossed it won't return! Thanks for the info on the autocross event - I can't make it tomorrow, but I am still interested in meeting up at some point. I can't PM anyone but staff at this point, I'm only at 37 posts...
 

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Discussion Starter #11
Hi all - thread update, by the very off chance anyone ever experiences something similar and could learn from my experience - got caught in another MAJOR downpour yesterday - hours worth of pouring rain. I was unexpectedly delayed while about an hour from home and was hoping to miss the rain altogether - NOPE!!! So, CHECK THIS OUT - I noticed the tail lights flashing randomly again, and even when I had the key out, it again thought it was inserted, and in position 1 (basically accessory position). Same exact symptoms as last time. Key fob wouldn't work the locks/alarm, etc. This time, I also had the joy of having the horn blare at random times - probably 10 times during the hours drive back home. Yes, this really pisses people off, as it would me. I got many confused looks of course, but I just wanted to get home, so I didn't stop. Any time the horn would go off, I was able to push it and it would stop, then go off again some random time later. I got home, pulled into the garage, shut 'er off and the horn blares continually until I got out and shut the door behind me (because that's when the horn should stop, right?? sheeeeesh). I then went immediately into the trunk and disconnected the battery (at the negative terminal). BTW, other than the horn randomly firing, the car ran perfectly fine all the way home in the pouring rain - no other strangeness at all. I proceed to check for water intrusion in the white box under the passenger cabin air filter, in the trunk, in the glove box, etc. Only water I detect is very small amount in trunk, which I have seen before, and which was far worse before I repaired the tail light gaskets, especially considering the many hours long downpour it was just in, and none I can see on any of the electronics back there.

So, I let it sit overnight with the battery disconnected, and everything opened up so it could dry out (hood, doors, trunk lid, trunk compartments, etc.). This morning I connect the battery and I hear some strange noise coming from the engine bay (oh joy!), as well as see the lights on the dash, as if key is in position 1, so I immediately disconnect the battery and have a helper come out to help me pinpoint where the sound is coming from. Through process of elimination, it is determined the sound is coming from the HORN in the front left corner of the car. So, I look up the fuse chart and remove fuse F3 in the glove box, which says it is for the horn. I re-connect the battery and.......BINGO!!! No more strange sound and no more strange ANYTHING. No lights on dash, key fob works perfectly and everything else I try works perfectly. Car starts and runs perfectly (sans horn of course). I come home and shut it off perfectly - perfect, perfect, perfect.

WHAT THE????? Could an issue like this with the horn (I assume it is full of water) really cause such a crapload of electrical gremlins to happen??? I plan to wait 2-3 days, like I did last time (I assume enough time to let all water evaporate), and will plug the horn fuse back in and see what I get. CRAZY!!!!!
 

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You have all the signs of the ignition switch sticking in the #1 position when the key is removed. Try jiggling the key next time. I don't know why this would only happen after heavy rain as it seems unlikely water can get to the switch.

Regarding the random operation of the brake lights and horn, try checking for water under the driver's side dash and around the steering column. The brake light switch and the horn relay are under there. Lay a garden hose on the top of the windshield with the wipers vertical so that water pours down over the lower seal and A pillar.

The horn filling with water would not cause it to go off as there is no power to it when the horn relay contacts are open. It has to be the steering wheel switch, the rotary contacts in the steering column or the horn relay, with the relay being the more likely problem in my opinion. Just in case, check for water in the steering column if you can.
 

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Discussion Starter #13
You have all the signs of the ignition switch sticking in the #1 position when the key is removed. Try jiggling the key next time. I don't know why this would only happen after heavy rain as it seems unlikely water can get to the switch.

Regarding the random operation of the brake lights and horn, try checking for water under the driver's side dash and around the steering column. The brake light switch and the horn relay are under there. Lay a garden hose on the top of the windshield with the wipers vertical so that water pours down over the lower seal and A pillar.

The horn filling with water would not cause it to go off as there is no power to it when the horn relay contacts are open. It has to be the steering wheel switch, the rotary contacts in the steering column or the horn relay, with the relay being the more likely problem in my opinion. Just in case, check for water in the steering column if you can.
Thanks for the great info 68FB - I tried jiggling the key both times this has happened, without success. I just checked it out again, and I think you may be spot on - I believe I hear a corresponding faint buzzing in the steering column area when I plug the F3 fuse back in. Is this a common leak spot on these vehicles (I imagine it's at the bottom of the windshield, where I can't see behind the plastic cover, which appears to be cracked a bit from age)? Perhaps the windshield is not sealed properly around the area above the steering column? I can't imagine it coming from anywhere else. Ugh. Currently I can say the car seems 100% happy with the F3 fuse out, but of course, no horn (not exactly the safest way to drive). Again, I'm hoping to get it dried out and completely back to normal. I've just been trying my best to keep her out of the rain completely, but that's not always possible in Upstate NY. I'd really like to stop the water from getting in if I can. I really appreciate your knowledge! Thank you!
 

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No, it doesn't seem to be common for windshields to leak into the cabin.

So the carpet under the driver's side dash is perfectly dry? I would have expected it to be a bit wet if water was coming down the inside of the firewall. There's a lot of sound-proofing insulation on these cars which may prevent water getting into the carpet, I suppose.

These pics from WDS show the horn relay and brake switch.

Horn relay picture.JPG

Brake light switch picture.JPG
 

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When water leaks in through the firewall under the pedals it's really hard to find any signs of it without pulling a lot of the carpet up.

I would also check the fusebox under the passenger chair for any moisture.
 

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Discussion Starter #16
Thanks much for the additional feedback and pics - helpful stuff. Check this video when you get a moment. It appears there is a line on the windshield indicating there was something up against the windshield at that level at some point in the past. I'm seeing cracking/flaking plastic bits. Perhaps it's not good thing that water is going down between the plastic and the windshield? Is something missing from the bottom of the windshield?

E39 M5 windshield bottom - YouTube
 

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Directly beneath that there is a plastic grommet plugging a hole in the firewall. When my car was leaking it was because that grommet was not there. Remove the cabin filter and you should be able to see if it's there or not. It's about the size of a dime.

Try shining a light from the inside of the car through the firewall and look under the hood for any holes.
 

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Thanks much for the additional feedback and pics - helpful stuff. Check this video when you get a moment. It appears there is a line on the windshield indicating there was something up against the windshield at that level at some point in the past. I'm seeing cracking/flaking plastic bits. Perhaps it's not good thing that water is going down between the plastic and the windshield? Is something missing from the bottom of the windshield?

E39 M5 windshield bottom - YouTube
You appear to have a strip of rubber trim along the top of the large plastic cover that runs along the bottom of the windshield that I don't have (10/2000). Regardless, this trim or the plastic cover aren't what seals the windshield so the damage you see is not the cause of any leak.

But Frye reminded me that the water running off the windshield runs behind the cabin air filters and drains through the body. The photo below shows the large drain channel with the filter removed. It's just above the yellow screwdriver. And the screwdriver is inserted in another drain hole that allows it to drain to the booster compartment. If that hole is plugged, water will build up in the wiper linkage cavity and get through the firewall if any of the grommets leak. You should check all the drain holes are clear and the grommets are in good condition.


DSC01573.JPG
 

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Discussion Starter #20
So the noise is not coming from the horn itself but near the stearing column?
I initially heard only noise from the horn itself (the kind of noise you would hear from an audio speaker if it were just barely making electrical connection - somewhat scratching sound, but quite faint), but if I listen really closely from inside the cabin, I can hear what sounds like a very faint electrical noise in the steering column area, as well as from the horn itself, when I plug in the F3 fuse. Each time I do it, sound from each area is fading, probably slowly drying up.
 
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