The Project Pad

Might be worth trying another cluster just swap in your speedo/odo. I saw one in the swapmeet forum

I have a cluster out of a 20v car sitting around.

Ah good spot, I might look into getting one to try.
Meanwhile I remembered we have huge sheets of thick fiberglass insulation sheet at work, so I tried some of it on top of the dashboard today, it's 90F and the sun through the windshield into the dash was probably a lot more and no warning light!

So I discovered joining the two wires behind the cluster removed the (O) brake pad warning symbol.
I never had the red 'brake' light lit by a single LED on, it comes in when the e brake is applied.
So I subsequently probably didn't need to change the brake bomb!

The warning I now have is 'brake light' is shown on the LCD screen accompanied by a loud beep, this is a very intermittent problem which usually happens during hot weather.
Other times it's great as it just says 'OK' when I start the car :-)

I've tried re-soldering the cluster and tried checking for poor contacts at the plug into the back of the cluster.

I'm thinking this is a similar system to the brake pad warning, but for the brake light circuit?
Can I disable the warning by short circuit some wires at the same plug as the brake pad wear circuit?

Anyone have a pin out diagram for the plug at the back of the cluster?

Yes, that is what you have to do. My avant had that done at one point in time. I believe you just short the two wires coming from the brake pressure sensor, but I don't know exactly which two those are to be honest... Doing it at the sensor might be easier.

Thanks for the help Chris, but now I'm very confused. I thought I had figured out there were 3 brake warning systems;

1) the red square that reads "brake" when the e brake is applied, also illuminates if the bomb is faulty etc. - mine is fine.

2) the LCD screen has a (O) symbol when the brake pads are low or the circuit is broken. Mine was the latter so I fixed it by short circuiting the wires behind the cluster.

3) the LCD screen has a "BRAKE LIGHT" message. Is this not for a brake light bulb fault? Or for the brake pressure sensor? Where is that?

Oh, now I'm confused too. Do you have a picture of the symbol? I may be thinking BMW now...

This is idling after work, about 90F in the car.
You can see no brake symbols are on.

Oh ok yeah... That's a light! Disregard what I said. Any of your lights out?

Sorry, I was pretty tired when I responded the other day!

Hehe no worries, I'm also having those long days at work. :-(

When that warning was on, I pressed the brake pedal and got Mrs Chappers to check the lights. They were fine.

I'm wondering if there is a signal wire to the back of the cluster that I can ground, but I need the pin out diagram for the cluster....I don't have a Bentley manual.

Should be the red wire in the same connector. It gets it's signal from the rear lamp control unit.

Hi Austin, thanks!
So I just ground the red wire?

That should do it.

Hmm I don't have a red wire in that connector block. You can see my previous brake pad wear indicator fix.

Where is the rear lamp control unit? In the trunk somewhere? Or under the rear seat?

Yeah in the trunk left side behind the carpet. The red wire is in the smaller black 14 pin connector.

Thanks Austin,
Ok I've found something Hella branded in the location you said in the trunk. I assume it's the light control module. The black connector has a red wire. If this is the signal wire to the cluster, I'll check continuity to the cluster to see which wire it is there and I'll ground that wire from the cluster.

Yes that is the control unit. I was talking about one of the smaller black connectors at the cluster. But yeah check the continuity between the two.

Great, thanks Austin. Feels like I'm finally getting close to fixing it!

Also what is the thing in the lower left of the picture? It looks like a horn to me...But it's in the trunk..

Horn for the alarm.

My car has an alarm!? Holy moly! I didn't realize that...
I only have a door key with it, wonder if the alarm still works...another job for another day.
Is there supposed to be a separate alarm fob to arm the alarm?

Mine will go off by unlocking the car via the door pin with the window open, and then turning the ignition. You can give that a shot if you want to test it out.

Hahaha just wait till you hear how wimpy it sounds!

It's so pathetic sounding.

Well I think it's fixed. While in the vicinity of the light control module I decided to check the condition of the wiring at the trunk lid hinge area. I found 3 suspect wires, one broke when I removed the tape.

I suspect these we're causing all sorts of issues and triggering the 'BRAKE LIGHT' on the dash screen.

I replaced the broken section in the wires with a new section, but with a loop in the wire to add a little strain relief and then re-wrapped it with electrical tape.

So far today, I've had no warning or bleeps from the dash, but it's not that hot today so I'm leaving the trunk carpet out just in case the problem didn't go away....

Nope, didn't fix it :-( still got the warning and beeping coming home tonight. it was 85f this evening as opposed to 80f today when it didn't happen at all. Interesting it's a small margin in temp triggers this...

I'll get back to checking more wiring then.....

I found no continuity between the red wire at the light control unit and the red wire in the 14 pin connector at the cluster.
Not sure if its supposed to be the same wire or not, either way I ran a new ground wire from the ground spot behind that little access panel at the end of the dashboard. I attached the ground to the red wire in the connector block at the cluster.
Fingers crossed that solved the 'brake light' issue.

I wanted to fix my inoperable sunroof for a while, I can operate it manually by the hand crank tool. It slides nice and tilts.
So I tested for power at the switch, the relay right there at the motor and nothing. I don't even get power to the harness at all.
I checked for power at the relay under the dash PN 443959257a, the window side gets power but the sunroof side gets nothing.
Is there a fuse in the circuit before that relay?