Brake light switch fails ON - How Common?

[Mo Brighta]

I've gotten word from two folks with my upgrade tails, the switch seems to fail in the ON position, which of course generates much heat within the brake light area. The early tails may be able to handle it (steel bulb plate), but the late tails have a plastic socket, so they tend to get all melty.


Without being too nosy, how many brake light switch failures do E30's see?
Is this common?


I realize that several things can cause an 'always-on' condition, such as loose mounting nuts and the switch coming loose , or a foot resting on the brake pedal (autos only, no doubt), maybe other conditions such as crud internal to the switch.


Any comments - what is your experience?

[e30davie]

it fails on because then at least people then think you are braking all of the time instead of never braking and hopefully dont crash into you....

do your upgraded lights draw more current than standard lights? if they do maybe the additional current is prematurely burning out brake switches?

Maybe theres a reason they made the bulb plate steel eh.

[Mo Brighta]

Fail-safe mode

it fails on because then at least people then think you are braking all of the time instead of never braking and hopefully don't crash into you....

Yes, this is the hope we all have...

do your upgraded lights draw more current than standard lights? if they do maybe the additional current is prematurely burning out brake switches?

Yes, they do - each lamp is only a few watts more, but having two brake lamps per side draws more than one. I think that switch failures depend more on the switch (plastic versus metal housing) than the load.

Maybe theres a reason they made the bulb plate steel eh.

Early cars mostly used steel for lighting internals, it was standard manufacturing. The first fives (E12) were about the first BMWs to use plastic reflectors from the start, along with late 2002s. Please correct me if I am wrong.

Most of my kits can use a relay to take the load of extra brake lamps. The trick in E30 trunks is finding a way to tap into another circuit (like the power antenna) for the relay power source.


Any input in that regard is most welcome...


Thanks!

[Zeemz]

My friend's brake light switch (behind the brake pedal) failed a little while ago, but when it failed his brake lights wouldn't light up. If I remember correctly, though it was more the mechanical part of the switch failed, not the circuit.

It is a pretty simple fix of just swapping out the switch though.

[MrBurgundy]

i vote for rob

[Mo Brighta]

i vote for rob

Toads don't cause warts

[MrBurgundy]

Toads don't cause warts

idk wtf that means

[agent]

When mine failed it was the switch itself as mentioned above, so no lights at all.

[Mo Brighta]

IDK WTF Either ...

idk wtf that means

Thank you, I was about to say the same ... who is rob, and what office is rob running for?


This is a thread about brake light failure and a poll about its various reasons. I was stymied when I saw that there are no 'rob' options in the poll.


Perhaps you can clear your meaning up for me?


Thanks!

[MrBurgundy]

You gotta have Rob on the options list for the poll.

To contribute to your cause though, I’ve never had a faulty BLS fail in the on position


Sent from my iPhone using Tapatalk

[JasonC]

Lol, was disappointed at no Rob option too.

But Rob was a mod and it goes back before I joined to have Rob in the poll.