Brake symbol won't go out.

[rs2315]

I was getting rear N/S indicator canceling under braking, so took a look and found massive corrosion on pins. Obviously a short going on, couldn't beleive anything back there was working the corrosion was so bad.
I replaced n/s and o/s bulb retainers, cleaned up female terminals with wire brush, was very gentle, then put everything back together.
Everything is working as it should except for brake symbol on dash won't cancel after pressing brake pedal.

All wires look good, fuse ok, and brake lights are working.

Any thoughts please chaps.

rs2315.

[Pirvu Eugen]

Its confusing...for me at least what symbol you have on the dash?

[rs2315]

Its confusing...for me at least what symbol you have on the dash?

The symbol that comes up when brake light bulb is not working.
It's a pic of a bulb with cross through it.

rs2315.

[johne]

Have you put one of the brake bulbs back in the wrong way round?

The brake bulbs have two filaments in them, one is 5 watts for the side light and one is 21 watts for the brake light. The brake failure sensor works on the difference in current flowing to each bulb to trigger it. Normally that would be approx 2 amps to the working bulb and nothing to the non-working one triggering the failure mode but 2 amps to one working bulb and only 0.5 amp through the incorrect sidelight filament would be enough to trigger a failure.

I know the "pips" on each side of the bulb are staggered to prevent this but with our holders it's possible to get the bulb in the wrong way round.

The other possibility is a broken filament fallen in such a way it touches the other filament inside the bulb causing extra current to flow.

John

[rs2315]

Have you put one of the brake bulbs back in the wrong way round?

The brake bulbs have two filaments in them, one is 5 watts for the side light and one is 21 watts for the brake light. The brake failure sensor works on the difference in current flowing to each bulb to trigger it. Normally that would be approx 2 amps to the working bulb and nothing to the non-working one triggering the failure mode but 2 amps to one working bulb and only 0.5 amp through the incorrect sidelight filament would be enough to trigger a failure.

I know the "pips" on each side of the bulb are staggered to prevent this but with our holders it's possible to get the bulb in the wrong way round.

The other possibility is a broken filament fallen in such a way it touches the other filament inside the bulb causing extra current to flow.

John

Thanks John, I'll give it a go.
I'll let you know how I get on.

rs2315.

[andyg plym]

is your power steering pump plug connected? had this on my old coupe where i had to sisconnect the plug on top to stop the break warning light come on.

if not this then must be the wires/terminals....been there before

[rs2315]

Have you put one of the brake bulbs back in the wrong way round?

The brake bulbs have two filaments in them, one is 5 watts for the side light and one is 21 watts for the brake light. The brake failure sensor works on the difference in current flowing to each bulb to trigger it. Normally that would be approx 2 amps to the working bulb and nothing to the non-working one triggering the failure mode but 2 amps to one working bulb and only 0.5 amp through the incorrect sidelight filament would be enough to trigger a failure.

I know the "pips" on each side of the bulb are staggered to prevent this but with our holders it's possible to get the bulb in the wrong way round.

The other possibility is a broken filament fallen in such a way it touches the other filament inside the bulb causing extra current to flow.



John

Problem solved, bulb was in wrong way round as you described in second paragraph.
Thanks for info John.
Also GT500 needs a mention

rs2315.