Brake Warning Light On Dash Kicking In When Braking

[ZeeGy]

After much browsing on your forums i could not find an anwser to the fault that i am having, so i decided to join here and ask for help, i know - not the way to start!

I own a 1990 (H) Toyota Supra Mk3 3.0Turbo 5 Spd Manual (7M-GTE)

Starded up my supra this morning, and all is fine, as soon as i move the car, say about 10 metres the brake warning light kicks in..... ((!)) and would NOT switch off!

After a few plays, i was able to find more issues with this - 1st thing i decided to check was the handbrake, so I totally removed the sensor switch on that..... the same problem occured... The only other thing that was suggested to me was that the supra could be low on brakefluid. again, not the case - there more than enough in there.

Guys/Gals - do you have any suggestions???

A footnote, the front brakepads are running low (about 3mm) im hoping that its a warning light for low pads, but i dont *think* that the supra had a warning light for low pads, nor would it engage so soon.

[Jinxed]

dont worry about the whole ur new an u have a problem thing ... the vast majority of people on here are very very decent good natured people that wont mind posting some help if they can offer any suggestion

and im sure someone will be along soon that may be able to offer good suggestions :)

[Leeky]

Park on a level surface - take the top off the brake fluid resevior.

Check the level, then pump the brake 5-10 times while the engine is running and check the level again.

If the level doesnt move then i'd say you can strike the levels off your problem list.

Its quite possibly your front pads are below the minimum and triggered the low light. yes indeed they do have one.

Let us know how you get on

[Karma Supra]

Well it seems you have gone over the "obvious" causes... already...

The first two things I would usually say are check the fluid level and handbrake light.

You are correct in thinking that the Mkiii does not have a low pad warning light (instead we have squeaky metal tabs)

Do the brakes feel ok? Are they spongey or feel abnormal in any way???

If so the may be an air lock, that compresses under braking to bring the fluid low enough to put the warning light on..

If not, check for the sensor wires shorting out on either the handbrake or fluid level sensor, as most sensor wires are negative switch activated...

If none of these cover it I'll rack my brains and we'll get it sorted

[Leeky]

You are correct in thinking that the Mkiii does not have a low pad warning light (instead we have squeaky metal tabs)

Didnt know, how strange. You learn something new every day

[Karma Supra]

I find it more effective... I once ignored the warning light for 6 months, untill I lightly rear ended a week old polo (in soarer no. 1) no damage barely touched lol.

The squeaking/scratching noise cannot be ignored at all and you have to sort it there and then!!!! Imagine chalk on a black board, long fingernaisl on plastic/credi card used as ice scraper type noise x 10. Very effective

[ZeeGy]

problem resolved!

Thank you for clearing up Karma, i did look at the brakes and couldnt find a warning sensor on there, or a cable for one....... the problem, and im kicking myself for this..... was a brake light bulb!!!!!

A twin fillament bulb popped, and one fillament broke, and then welded iteself onto the other fillament, creating a short circuit and triggering the brake sensor.

The brake sensor is prone to corroding too, and causing the same problem... its a blue box found just under the offside tail lamp, i opened it up, cleaned all the connections (with some electrical acid cleaner) and resealed the unit - all is fine now...

I thought i would mention what i found, as by the sounds of it, I wont be the only one that asks this question, so as its here for all to see :)

guys, thanks for your help.

[Karma Supra]

Good work!!! I have never heard of a blown bulb causing the handbrake light to stay on before!!!!

The blue box controls the light fail diagnostics system (you are right, they get damp, corrode and usually need replacing!)... usually an orange light that looks like two brake lights illuminated is constantly on, but it shouldn't have been causing your problem as it controls a different dash light!

[ZeeGy]

Good work!!! I have never heard of a blown bulb causing the handbrake light to stay on before!!!!

The blue box controls the light fail diagnostics system (you are right, they get damp, corrode and usually need replacing!)... usually an orange light that looks like two brake lights illuminated is constantly on, but it shouldn't have been causing your problem as it controls a different dash light!

indeed - but that may be due to the short circuit - hey ho, im happy now

[Karma Supra]

So you should be ;)