smoke Smoke SMOKE!!!

[pgrindstaff]

So I am driving into work this morning and smell smoke. Naturally I turn off the fan and close the sun roof thinking it was coming from outside. Wrong. The smell gets stronger and when I look down at my cluster I notice smoke coming from behind it. After the initial "Oh ****" reaction, I find a place to pull over to check it out. Now I should note that this smoke has the distinct smell of burning electronics, possibly melting plastic. I open the hood to check the fuse box, everything checks out. Pull the rear seat to check there, aok. :S

Well, at this point I am somewhat confused as no errors have displayed on the check control and all accessories work fine. I can dim and brighten the lights on the cluster, move the steering wheel forward and back, windows up/down, etc. One thing a co-worker noticed after I got to work was that when the headlights get turned on, the engine revs a little. I guess the alternator kicking in or being stressed?

I have a service appointment tomorrow morning to have the problem looked into but have every intention of pulling the cluster and lower dash apart to see if it is something simple, and if it is, will cancel my appointment.

Obviously this type of thing is hard to diagnose without tearing into anything but any ideas you guys have are more than appreciated.

Thanks,
Patrick

[bsell]

Check your grounding straps from the engine to the chassis. I suspect an intermittent ground problem, causing the engine to become isolated from the body wiring, which causes a spike in the alternator volatge output (it doesn't 'see' the battery, so the volts go shooting up).

While you are poking around the engine compartment, make sure your motor mounts haven't given up the ghost, allowing the engine to rock around and take out your grounding straps.

If you can, find out what the voltage does, both at the battery and on the engine, when you play with the lights and the engine revs. This will help confirm my guesstimate or show me to be full of it!;)

Brian

[pgrindstaff]

Just a little update:

Without any real testing, as I have just gotten home, I have decided that the problem seems to be directly related to the headlights being on. There was no sign of smoke or smell all the way back home, with the lights off the whole time, with the exception of the turn signals. This may not be extremely significant but I personally found it strange that the visible smoke, if absolutely related to the alternator, ended up coming through the cabin at the cluster.

Also, please excuse my ignorance, but how exactly does one check the voltage at the engine? Do I need to crawl under and get to the alternator to check it?

Thanks for the help,
Patrick

[bsell]

It is not impossible that your headlight switch has an intermittent short within it. You might get lucky and see the flash from the arcing caused by an internal short if you operate the switch in the dark.

To measure the voltage on the engine, with the engine running and being mindfull of the moving parts, put the positive lead of your tester on the alternator output (+) and the negative lead on the engine.

Then move the negative to the chassis and see if the voltages are different. If they are, you have connectivity problems between the engine and the chassis. To define the problem as ground related, put the positive lead of the tester on the engine and the negative lead on the chassis. You can do this same thing all the way back to the battery, on both the positive and negative sides. There should be minimal difference if all is well.

Brian

[pgrindstaff]

I went ahead and pulled both the fog light and headlight switches to check the connections and wires and everything looked just fine. I looked around with a flashlight at the wires as best I could and did not see any wires that appeared to be damaged. What is interesting is that the smell is only present on the left side, in the dash, and not the right, behind the switches. I am contemplating pulling the cluster out and taking a better look but I haven't decided yet. I just hope that terrible smell goes away soon.

Investigating further I pulled the kick panel to check the rest of the wires below the dash. Same deal, everything looked just fine but smelled like burnt wire/electronics.

I checked the voltage at the battery between the posts and grounded and the numbers looked good. I did not test the voltage at the engine as I could not get the car on ramps this afternoon. The ground strap looks to be ok, as well as the mounts. I also went ahead and made sure that each fuse was the correct amperage in both fuse boxes as well.

I started the car to reproduce the headlight problem and what do you know, just like every time you try to show someone else what is wrong, everything worked fine. No higher revs, flickering of lights, anything. Typical...

I decided to cancel my appointment at the dealership as giving an arm and a leg for them to diagnose the electrical system doesn't seem to be the way to go at this point. Like I said above, I do not know if I am going to pull the cluster or not. Probably better safe then sorry I guess.

Brian, thanks a ton for your input, you have been a great help.

Patrick

[Ferret]

Then move the negative to the chassis and see if the voltages are different. If they are, you have connectivity problems between the engine and the chassis. To define the problem as ground related, put the positive lead of the tester on the engine and the negative lead on the chassis. You can do this same thing all the way back to the battery, on both the positive and negative sides. There should be minimal difference if all is well.

Brian

The best way I find to detect engine ground problems is to get a voltmeter, connect one terminal to the engine block and the other terminal to the car bodywork! (Like you've suggested)

If it shows up a voltage, you've got a faulty connection between the block and body - a resistance somewhere is causing a voltage drop that's being detected by the meter.

[bsell]

So you say the smell is on the side of the dashboard with the headlight adjuster? If you have looked at the headlight adjuster switch and it is working fine and smells alright (i.e. just 'old' and not burnt) then I figure the smoke from the cooked wires would rise so following the smell down should lead you to the hot wiring. This kind of problem sucks because nothing stopped working permanently, making it much harder to find out who in the dashboard is sick.

I too wouldn't want to pay dealership labor rates to find an intermittent electrical problem, plus, they probably don't want this kind of business as it is a lose-lose situation for them and their mechanics. These kinds of problems chew up the hours and most folks don't want to pay for this, so the service writers get yelled at by both the customers (for the cost) and the mechanics (for undercharging the customer for the hours spent fixing the car).

This kind of repair will test your patience but once you find the problem, you will have become much more 'intimate' with your car than ever before.;)

Best of Luck,

Brian

[pgrindstaff]

I went ahead and checked the voltage at the engine (pos lead on engine, neg on body and vice versa). I read a minimal voltage, .00x. on the right side and .000 on the left. I think the voltage showing on the right side was probably just a fluke, and most likely nothing to worry about.

Now the fun begins with pulling the cluster. I should have pulled it last night when I had everything apart and could have easily dropped the steering column. Oh well, gotta do what you gotta do.

[pgrindstaff]

Not that anyone really cares but I found the source of my smoke. On my way to lunch today, a coworker driving behind me noticed I had no brake lights. After determining that he was right, and the bulbs looked ok, I started looking for a cause. Check Control offered no help and never threw BRAKE LT CIRCUIT, which was definitely strange to me. After I got home I opened up the LKM to check for cold solder joints, checked the wiring in the trunk, which BMW changed between my 530 and my 540 (no more exposed wire loom), and continued under the dash to find the brake light switch melted. The wiring looks fine, so another new switch will be going in tomorrow. That will teach me to save a few bucks by going to ebay for a brake light switch now wont it.

Thank you all for the suggestions and guidence you provided above. Too bad I didn't think to look at the new switch in the first place.

[Ross]

I'm pleased it is figured out and also that you posted the ultimate resolution, so many threads are left without a solution and no one learns anything.
Was this a used ebay part or some cheesy offshore knock off? If used, "oh well" is about all you can say, it was probably 15 or so years old already.
If this was a new part I suggest posting the part's description and sellers info. Our old cars enough maintenance without failures due to crapola parts.
By the way, the reason you never got a brakelight circuit warning is because when the switch burned out it left an open circuit(fortunately), the LKM never knew you had touched the brake pedal.

[pgrindstaff]

The switch I got looked to be a brand new OEM part sealed in a plastic bag. Now there was not a sticker with a part number or anything but the switch looked identical to one shown on pelican parts (red plastic ring). I am not sure what the difference is between the switch with a white and red plastic ring. Different manufacturer maybe? Anyway, I can't say that the switch coming from ebay had anything to do with the switch being fauly. I would say it was a bad switch straight from the manufacturer and had nothing to do with the ebay seller.

[Jehu]

Unless the seller sources his part from a Chinese knock off supplier... The Counterfeit Industry in China is staggeringly massive in scope and corrupt influence. So far my Chinese Fog-lamps haven't fallen apart but then again the only real electrical part is the Bulb which as far as I know didn't come from a Chinese knock off operation.