So wondering if you guys can help me out...

a week ago i replaced my brake light switch because my other one died. Well yesterday my exterior rear brake lights just stayed on even when i'm not braking. I checked and the brake pedal IS making contact with the brake light switch so it should be off? I can use my foot to push the brake pedal upward like .0001" (meaning it barely even moves) and it will turn off, but if i let go it will light up again.

If i'm driving at a steady speed it will stay off, until i shift gears, it will come back on. One interesting thing i found out today is that if i'm parked with the engine running, I can get the brake lights to stay off.... UNTIL i rev the engine a little bit, then all brake lights get lit. weird?

There is a small whine when revving/driving slowly that lead me to think "alternator". But i tested the voltage when the car is off: ~12.5v and when the car is running: ~13.98v

seems ok right?

i don't know what's going on. can it be another faulty brake light switch? any suggestions helpful! thank you!

 

So the brake pedal is contacting the brake light switch at rest? That's why your brake lights are on...

Adjust the switch.

 

i was under the impression that when the brake light switch is pressed, brake lights are not on. when the switch is released, brake lights get lit?

so when you press the brake pedal, the pedal does not make contact with the switch so the brake lights turn on.

is it not this way?

 

Oops, I was thinking opposite for some reason. They're both mounted above the pedal, correct? If so then yes, you are correct.

Have you tried adjusting the switch downward? If the slightest pressure upwards onto the switch makes them act normally, then it's likely out of adjustment.

 

yea ill make an attempt at that i guess...
i just found it weird that when i revved the engine a bit, the all brakes lights would light up.

I jumpstarted my car when my car died (because of the brake lights) and there is a slight high pitch whine when im driving at low speeds. is this because of the alternator?

thanks

 

theyre relatively sensitive switches. chances are, if you only need to pull up on the pedal as slightly as it sounds, the revving of the motor is creating a resonant band frequent enough to touch the contacts. in which case you just need to adjust it a bit. although i could be way overthinking it, cuz im pretty guilty of that alot

 

except the switch just doesnt seem to work like theres a short before the switch . . . . i tessted the switch with a multimeter its opens and closes as it should but doesn't shutoff the brake lights tail lights w/e lol the thre lights in the back of the car that should come on when you press the brakes, also i can shift out of park without pressing down the brakes either theres two switches one on top its brown and one on bottom its black what switch does what ? any help would be greatly appreciated thank you 2005 Maxima 3.5 automoatic se

 

Yes, when an alternator is putting out its max, you will hear a whine. Since the battery was discharged, the alternator is working its little heart out.

 

Diconnect the two wire connector at the brake switch. It should have a Red with Yellow stripe and Red w/ green stripe wire. Do the brake lights go on even with the switch disconnected? If they don't go on with the switch disconnected I would expect the problem to be with the switch.

You may want to remove the switch from its mounting and just work it manually. Does the switch/brake light circuit operate normally if you depress the swith manually?

Do the brake lights remain off if you remove the stop lamp fuse #10 (15Amp)?


Are there two switches down there? Are you working on the wrong switch? Were any kind of wiring modifications done? It really is a simple circuit, hard to mess it up.

 

Brake lights come on by themselves if engine revs increase? That's just plain weird. Anyone mess with the wiring on this car?

 

did u purchase a used switch...jus curious.

I wd say adjust the switch and check wiring.

 

update?

 

You might want to check the little rubber/plastic stopper that the switch rest on. If that little pad fails the end of the switch will stick thru a hole and the light will stay on all the time.