Brake lamp warning

[jswest69]

In my 88 vert I inconsistently get the brake lamp warning. I used to get it all the time and found that that issue was the 3rd brake light and fixed that issue by wiring around it. No it stays off most of the time but occasionally comes on only when I turn the right blinker on. Have the right bulbs installed and all connections are good so kinda stumped. Anyone have this problem before?

[jlevie]

This could be corrosion in the bulb sockets, at the connectors, or a bad brake light switch.

[jswest69]

Ya, checked everything like that except the brake light switch. Will give it a try but I am not even touching the brakes when it comes on. Just the right turn signal. doesn't make much sense.

[jlevie]

Ya, checked everything like that except the brake light switch. Will give it a try but I am not even touching the brakes when it comes on. Just the right turn signal. doesn't make much sense.

In that case I'd say there is a wiring problem that is feeding power from the turn signal circuit into the brake lights circuit.

[Semblance]

Try new bulbs too, everywhere. Had this problem, replacing the third brake light bulb,which was working, fixed the problem.

[jswest69]

All new bulbs already, cleaned every socket and connection, eliminated the third brake light check circuit. Will try a new brake light switch. Thanks for all the suggestions.

[jswest69]

New brake switch didn't work either. It is a mystery...

[FLG]

I remember German audio specialties (forgot his name on here) has a post somewhere about cleaning something.. Perhaps it's on the board itself, I can't remember exactly but do a search and I'm sure u can dig it up

Sent from my SCH-I545 using Tapatalk 2

[McGyver]

The Check Circuit that was mentioned will be mounted behind the rear seat side panel on the drivers side. check to make sure all of the wires are clipped in properly, and maybe ziptie the plugs in.

[Semblance]

No, on verts it's not behind the seat, it's in the third brake light, which he's already bypassed. Dunno man, check your grounds? Try to find Luke's thread as FLG suggested, he talks about cleaning the ground connection inside the tail bulb holder. When I was tracking mine down, I actually couldn't clean mine, i couldn't pull the connectors apart, but maybe it will be easier on yours.

[McGyver]

No, on verts it's not behind the seat, it's in the third brake light, which he's already bypassed. Dunno man, check your grounds? Try to find Luke's thread as FLG suggested, he talks about cleaning the ground connection inside the tail bulb holder. When I was tracking mine down, I actually couldn't clean mine, i couldn't pull the connectors apart, but maybe it will be easier on yours.

You're talking about something else. And as i said, the check panel circuit/relay/boxy-thing is not behind the seat, it's behind the side panel in the back on the driver's side. (as opposed to next to the antenna on a coupe) This panel may have a bad connection or be broken and causing the check panel to light up.

[Liquidity]

Try new bulbs too, everywhere. Had this problem, replacing the third brake light bulb,which was working, fixed the problem.

If replacing a working bulb fixes a problem the problem was a loose connection but most of these problems come from using the wrong type of bulb from the start. The base has to be the correct metal or else it will galvanize against the socket. Multiple bulbs will fit the same socket but only the one with the right metal base won't galvanize. Something else you can do to prevent the corrosion is put some dielectric silicone on the bulb before you put it in.

[jlevie]

The logic of the brake warning light is the AND of power to the circuit and all three current sensors. If the result is true, the LED turns off. If false it turns on. The power up state of the logic is for the LED to be on, which is why you have to step on the brake after starting the car.

Since the OP stated that the right turn signal can activate the warning, the only logical explanation is a wiring problem that is allowing at least some power to reach the brake circuit. If that leakage is insufficient to allow full current flow, the LED will turn on.

[Semblance]

You're talking about something else. And as i said, the check panel circuit/relay/boxy-thing is not behind the seat, it's behind the side panel in the back on the driver's side. (as opposed to next to the antenna on a coupe) This panel may have a bad connection or be broken and causing the check panel to light up.

So if I remove my rear seats, and remove the interior black panel so I'm looking at bare metal, there's nothing there. Is it actually inside the body, or am I looking in the wrong place?

[McGyver]

So if I remove my rear seats, and remove the interior black panel so I'm looking at bare metal, there's nothing there. Is it actually inside the body, or am I looking in the wrong place?

i have a 1989 325i convertible, so unless your vert is different, you will need to remove the rear seat and the interior panel on the driver's side. The little circuit/relay thing will be in the cavity somewhere behind or below the speaker inside the body panel.