3rd brake light always on

[MacRob]

Went out tonight and noticed the high level brake light was on. Unlocked car to investigate and noted that the indicators didn't flash when the doors were unlocked.
Tried starting the car and all good but the 3rd brake light still on.
Any ideas as to why both is happening?

[Maxfly]

Originally Posted by MacRob

Went out tonight and noticed the high level brake light was on. Unlocked car to investigate and noted that the indicators didn't flash when the doors were unlocked.
Tried starting the car and all good but the 3rd brake light still on.
Any ideas as to why both is happening?

I would guess the switch is faulty or needs moved back into position. It’s situated fairly high up on the brake pedal, reach up and feel the switch and push it back into its housing (push towards the rear of the car). If that’s doesn’t work I think a new switch may be required

*edit* replying too quickly without enough thought! As you clearly state it’s just the high level brake light, my answer really only suits if it’s all brake lights!
Do you have led bulbs fitted at all? Sometimes the high level light will illuminate (not too brightly though) if most bulbs have been replaced by leds’s

[MacRob]

Originally Posted by Maxfly

I would guess the switch is faulty or needs moved back into position. It’s situated fairly high up on the brake pedal, reach up and feel the switch and push it back into its housing (push towards the rear of the car). If that’s doesn’t work I think a new switch may be required

*edit* replying too quickly without enough thought! As you clearly state it’s just the high level brake light, my answer really only suits if it’s all brake lights!
Do you have led bulbs fitted at all? Sometimes the high level light will illuminate (not too brightly though) if most bulbs have been replaced by leds’s

Yes, I do have LEDs in the rear but have been in the car for over a year with no problems. It's strange that it started the same time indicators have stopped flashing when the doors are locked/unlocked

[Maxfly]

Originally Posted by MacRob

Yes, I do have LEDs in the rear but have been in the car for over a year with no problems. It's strange that it started the same time indicators have stopped flashing when the doors are locked/unlocked

Maybe try the old off and on again - disconnect battery for 30 mins the reconnect see if that works?

[SD1too]

Originally Posted by MacRob

Went out tonight and noticed the high level brake light was on. Unlocked car to investigate and noted that the indicators didn't flash when the doors were unlocked.

Hi Rob,

When you turn on the hazard warning lights, do the direction indicator warning lamps in the instrument pack flash?

With the ignition switched on (key position II) does the "door open" warning in the instrument pack illuminate?

Simon

[MacRob]

Originally Posted by SD1too

Hi Rob,

When you turn on the hazard warning lights, do the direction indicator warning lamps in the instrument pack flash?

With the ignition switched on (key position II) does the "door open" warning in the instrument pack illuminate?

Simon

No they don't come on yet are working fine.

[SD1too]

Originally Posted by MacRob

No they don't come on yet are working fine.

Thanks Rob. That tells us that you have a K-Bus communication fault with the instrument pack (source: RAVE). That's likely to be responsible for the strange behaviour of your high level brake light.

Simon

[MacRob]

Originally Posted by SD1too

Thanks, Rob. That tells us that you have a K-Bus communication fault with the instrument pack (Source: RAVE). That's likely to be responsible for the strange behavior of your high-level brake light.

Simon

Slapped my laptop on it with TOAF today. It wouldn't let me read the LCM and BCU but would read fault codes. It came up with a fault on the LCM. Popped that out to have a look and sure enough, there is corrosion on it around the alloy fins.
Think its safe to say I've located the problem. The only way to be sure is to test it with another unit. won't be a perfect solution but will give me a fuller idea.