Phantom Brake Light on Check Panel

[MA325is88]

+1 to Luke, but in addition to all that I also had a bad check relay. It was replaced, and the problem was gone.

[JamesE30]

And JamesE30, fire your asshat mechanic. You have a retard on your hands.
Luke

lol I thought so...
My only problem is they cant get the "inspection" light to go off.
The brake warning light they could fix for a bit of cash, but I'm not fussed by it...

Thats very helpful information though thankyou.

[StereoInstaller1]

James, you can fix your "INSPECTION" light for free, using a short chunk of wire.

Read this: http://www.unofficialbmw.com/repair_faqs/sil.html

Luke

[E30 Cabrio]

Thanks, as this is more helpful advice than some of the generic comments made that didn't apply to my situation.

Ironically, the problem has disappeared just as mysteriously as it appeared.

I'll poke around the trunk and clean all the contacts this weekend.

Thanks again.

Guys, I am gonna speak on this. Trust me, I truly know my shit.

OK first:

THE STAINLESS BASE BULB THEORY IS BULLSHIT!

Any normal bulb is just fine. This circuit is just not that sensitive. Use those WalMart bulbs all you want, they are the same electrically.

The "bad brake switch" theory is wrong too. The circuit sees a bad switch as simply not using the brakes...absolutely no bearing on the DIC LED being on or not. Simple logic should tell you that, but old bullshit internet rumours die hard.

The real issue is simply oxidization, 100% fucking guaranteed. Do EXACTLY as I say and all will be fine...total cost of about $6. Maybe an hours work.

How to fix your issue:
1. Buy a can of CRC "Electronic Circuit Cleaner", should be about $6
2. Remove both the taillight assemblies from your car
3. Find the ground point of the panel, where a cheesy little wire connects all of the bulbs to ground....TAKE IT OFF and clean it with the CRC. Use a pencil eraser if it is really bad, but get that fucker clean!
4. Remove the left trunk liner. In front of the antenna, find the 2 screws that attach the diode board that controls the taillights (NOTE: Not the amplifier, OK?) remove it and clean the contacts of the board (AFTER unplugging it!) with more CRC.
5. CLean ALL of the plugs (more CRC...see a pattern?) that attach all wiring...meaning, the the third brakelight, both taillight housings AND the diode board.
6. Reassemble, making certain to properly seat ALL plugs. Don't forget to reattach that diode board! The better you clean those connections, the more likely your problem will not come back for another 20 years.

Now, when you start the car, the "CHECK" on the instrument cluster should come on, as should the "BRAKE" indicator on the DIC. Tap the brakes, both will shut off...unless you have a bad bulb.

And JamesE30, fire your asshat mechanic. You have a retard on your hands.

Luke

[deansbimmer]

Props to Luke. This has been an issue with my e30 since I bought it. This fixed it and now my check panel is 100% clear! :D

[E30 Cabrio]

I would try what nando suggests - and the stop light switch ran me about $6 last time I bought one online.

And yes, I read all of your post(s).

:-)

EDIT: the Brake light switch is $5.83 at fap99.com, the place I bought the spare one I keep in my track box.

Thanks for the link to fap99.com

They have good pricing on parts.

[mark1]

I'm having the same problem with my cab after the left light assembly was replaced and 3rd trunk lid light remounted on a new lid. Can't find the diode board by the antenna. Is that the small board in the 3rd light on the trunk lid?

[deansbimmer]

Its sandwiched between the stereo amp and the fender. Its mounted to the amplifier standoff and is a silver relay looking box.

[LINUS]

I'm kind of a hick, and I use a lot of auto experience from the 4x4's I've had on my cars, and one thing I do is white grease my electrical connectors - might be the exact thing that Luke is doing, just not as nice of a chemical.

Double check your plastic clips are are holding in place the metal retainer plate - my clips were brittle & broke, so I JB'ed mine in tight - otherwise the bulbs don't get good tension against the spring arm putting juice to the bulb.

And I might be on crack with the grease thing, but it helps when you get your electrics wet on occasion.

[E30 Cabrio]

Well, the problem reappeared briefly earlier today.

The plastic brake light housings are in excellent condition and the brown ground wire and the connectors to the plastic housings are pristine and show zero signs of any corrosion.

I followed the wire harness, but lost track of it near the power antenna and didn't feel like tearing the trunk lining out as it's getting dark.

I suspect that the problem might be corrosion in the 3rd brake light assembly, as at one time, it had an aftermarket cell phone antenna mount drilled thru it, and had a threaded plastic cover on it until recently.

I bet some moisture got in there.

I'll take the 3rd brake light housing apart and examine the wiring, as the wiring, housing and connectors in the trunk look brand new.

I will also poke around the trunk some more for the relay when I have more daylight.

[clavinZERO]

I'm kind of a hick, and I use a lot of auto experience from the 4x4's I've had on my cars, and one thing I do is white grease my electrical connectors - might be the exact thing that Luke is doing, just not as nice of a chemical.

Double check your plastic clips are are holding in place the metal retainer plate - my clips were brittle & broke, so I JB'ed mine in tight - otherwise the bulbs don't get good tension against the spring arm putting juice to the bulb.

And I might be on crack with the grease thing, but it helps when you get your electrics wet on occasion.

The stuff meant for this is cheap too, called DIALECTRIC GREASE, same stuff you can rub onto your spark plug wire rubber tips (helps em not stick I guess). It's good for pretty much all electrical stuffs. It insulates the connecting surfaces from oxidation, etc.

[StereoInstaller1]

I will 100% agree with dialectric, or with vaseline (serious hickteck) especially on the bulbs themselves...insualtes somewhat from rattles, too.

The CRC will fairly effectively clean corrosion off with just a spray, that is why I recommend it.

Luke

[nando]

I'll say it again, and only once more. it's the brake light switch...

[87Blue325iC]

my brake warning light comes on occasionally when i turn the car on,
As soon as i touch the brake it goes out,

That is what it is supposed to do...

[87Blue325iC]

James, you can fix your "INSPECTION" light for free, using a short chunk of wire.

Read this: http://www.unofficialbmw.com/repair_faqs/sil.html

Luke

Just did this last night (used a different FAQ then the link above - but it says the same stuff). Worked like a charm.