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From digest.v4.n826 Wed Jul 10 19:42:29 1996
From: Larry Schwarcz <>
Date: Wed, 10 Jul 96 19:25:23 -0700
Subject: Re: Brakes and Rear speakers for <e30> 325iC

sdallas_at_MIT.EDU (steve dallas) writes:
>I told them I had a problem with the Brake Light (!) indicator on the CHECK
>panel that is near the overhead light. As a result, they told my my brake
>pads and rotors needed to be replaced. This sounded wrong to me, but I went
>ahead and did it. They also replaced the brake lamps in my rear panel. But
>sometimes, after driging a few hours, the Brake Light (!) indicator still
>comes on, for no reason that I can tell. Anyone know why?

Well, I had this same trouble on my '90 325iC. A local dealer told me the two most likely causes on the convertibles is the center brake light assembly and the brake light switch (by the brake pedal). This question comes up enough that I wrote up this summary:

Brake Check Light:

The normal and correct behavior is for that light to come on when you start the car. Then, once you depress the brake pedel, it should go out.

When the car starts, it can't check the brakes, so it assumes they're bad. Then, once the brake pedel is pressed, the system then can see that they're OK and goes out.

Now, if the light stays or comes on later, then there's lots to go bad (I had this problem on my '90 325iC).

Possible causes:

  • Bad bulb. This is an obvious cause. First, check to see if you actually have a burnt out bulb. If you do, replace it. If they're all OK, replace all three of them (L, R & center) anyway. Even though they all light up, you could have a filament that's on the verge of going out. It's the cheapest and most likely solution. COST: About $7.00 for three bulbs (the center bulb is more expensive

    than the others).

  • Bad contacts. Try cleaning all the bulb contacts. Disassemble the tail light assembly and do a *very* thorough cleaning of all the connections. COST: About $7.00 for a can of switch cleaner.
  • Replace the brake light switch (by the brake pedal). It may even be a bad connection. On my car, the problem was that the plug was not quite plugged all the way into the switch. I just had to securely attach the plug.
  • Center stop light assembly (on convertibles only). On the iC's, this light is mounted on the trunk lid and is subject to damage more abuse each time the trunk is shut. I also have an extra one of these in working order. Call me if you need one.
  • Brake Check Relay. About $100 for a new one. I've got an extra if anyone needs one. I thought mine was bad and bought a new one. I've still got the old one. (See below on location for Brake Check Relay)
  • Check control panel (the box with the check lights by the mirror). For my car it's $222 with my BMW CCA discount from The BMW Store. According to a local dealer, it's very rare for this part to fail. There's a step-by-step diagnositic process in the shop manual (BMW, not Bently).
  • Bad ground. The tail and brake lights are all grounded at the ground point G300. On the E-30 convertibles, this is right by the Brake Check Relay. The Brake Check Relay is under the left (drivers) side side panel in the back seat.
  • Connector problem in circuit board on instrument cluster. See posting from Laurence G. Hoffman on the WWW site for more details on how to trace and fix these type of problems.

To get to the Brake Check Relay and G300 on convertibles:

  • Remove the back seat (bottom and back).
  • Remove the trim around the soft top release latch by sliding it towards the rear.
  • Pop out the panel that covers the drivers side (left) speaker (pull from the top side).
  • Undo the two larger black phillips screws that hold the panel.
  • Open the drivers door and pull away the black weather strip.
  • SLOWLY pull the side panel out. The speaker wire will be connected still. When you get enough clearance, disconnect the speaker.

The ground will be the bolt at the bottom center with a bunch of wire attached. The Brake Check Relay will be visible through the hole above the ground connection. It's a larger relay (about 4") with 2 large plugs. It's attached with two screws.

The Brake Check Relay is in the trunk on coupes near the antenna. I don't know where the ground point G300 is on the coupes.

If you have more questions about this, feel free to e-mail me.

>My right rear speaker is out (no sound at all), and the left rear speaker
>drops out sometimes. It comes back if I hit it. But I am afraid that this
>solution is not a permanent one. I told the Service people about it, and
>they told me the speakers needed to be replaced. They said the replacements
>were $50.00 each. I was wondering if anyone elase had problems with these
>speakers, and if it would be an easy job to replace them myself.

Sounds like a good time to replace them with good ones. Those speakers are just 4" dual cones. I've been meaning to replace mine sometime. Any suggestions on drop in replacements (no drilling) that can be powered with the 20 watts/channel from the stock amp?

         Good luck!
Lawrence R. Schwarcz, Software Design Engr/NCD      Internet:
Hewlett Packard Company                               Direct:  (408) 447-2543
19420 Homestead Road MS 43LN                            Main:  (408) 447-2000
Cupertino, CA 95014                                      Fax:  (408) 447-2264

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(c) 1996 Elmer Fudd. All wights wesewved.

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