overhead indicator "brake light" - all bulbs fine, what could it be from?

[StereoInstaller1]

it's the brake light switch that's under your brake pedal,

it's going to be the PC board for your 3rd brake light.

I will disagree with both of these. The issue is resistance being inaccurate. The chance that the PC board having a bad load resistor is highly unlikely.

That being said, the first thing I did was to replace that panel with a "known good" one. No improvement at all.

If the switch were bad, the system would not know that the pedal were being pushed, thus the system would have no issue. An intermttent brake light switch would be the same as a spastic leg on the pedal...no issue for the system.

With the inaccurate resistance being the only issue remaining, go take apart your tail light housing adn LOOK at the ground connection to the bulbs. You MUST seperate the metal backing plate from the plastic housing to see the one I am referring to, a single brown wire that supplies ground to all of the bulbs. I can damn near promise that is the issue. All of them I have ever seen are burned, with 2 of my spares blackened. All of them are melted. All of them have a major voltage drop.

Luke

[E30 Cabrio]

I will disagree with both of these. The issue is resistance being inaccurate. The chance that the PC board having a bad load resistor is highly unlikely.

That being said, the first thing I did was to replace that panel with a "known good" one. No improvement at all.

If the switch were bad, the system would not know that the pedal were being pushed, thus the system would have no issue. An intermttent brake light switch would be the same as a spastic leg on the pedal...no issue for the system.

With the inaccurate resistance being the only issue remaining, go take apart your tail light housing adn LOOK at the ground connection to the bulbs. You MUST seperate the metal backing plate from the plastic housing to see the one I am referring to, a single brown wire that supplies ground to all of the bulbs. I can damn near promise that is the issue. All of them I have ever seen are burned, with 2 of my spares blackened. All of them are melted. All of them have a major voltage drop.

Luke

I've had 2 E30's with the same issue, and both times the culprit was the 3rd brake light PC board.