Help brake lights stuck on... :(

[ginmtb]

Okay like the title says, my brake lights are stuck on. Things that have changed before it started happening:

- wired up the brake sensors on the master cylinder
- adjusted the parking brake switch just a bit so the light on the dash would come on when it was supposed to

So in my troubleshooting I have tried undoing what I did above. No luck. I bought a new brake switch no luck. I have taken both switches from their location and while they were plugged in I pushed them in to see if there was something going on with the switches.

Anyone have any thoughts? The fluid in the master cylinder reservoirs is exactly where it had been since I have swapped it out for a new one.

Thanks!

 

[fhawk5]

Well, +12 volts coming from somewhere. Multimeter , and follow trail.

 

[Solace in Solitude]

Is your brake pedal return spring, returning the pedal sufficiently, to turn the lights off?

 

[JohnnyC]

Is your brake pedal coming all the way back tripping the brake switch?

 

[ginmtb]

Interesting now my license plate light doesn't light up...

 

[landcruiserrich]

The switches on your master cylinder should only be wired to the little red light on the dash. Same with the e brake switch. The only switch that should be turning your brake lights on is the switch connected to the brake pedal. At least thats how mine is anyway.

 

[ginmtb]

So I pulled the brake switch out completely (took apart the dash). So I have full access to it so can depress it and release it fully. So yes it can fully return...

 

[ginmtb]

In other words I can depress the switch manually and release it manually and that has no impact on the lights...

 

[ginmtb]

Here is the warning light wiring setup I referred to:

 

[landcruiserrich]

And when you unhook the brake light switch do the lights go out?

 

[ginmtb]

And when you unhook the brake light switch do the lights go out?

Didn't try that but indeed it does kill the lights. It is a brand new OEM switch... So wondering if it is the connections to that...

 

[bj40green]

It's a double action switch. The break pedal keeps the switches open when the pedal is up.
When you depress the pedal, A-A' close first. A fraction later B-B' will close.
If you have the switch in your hand both sections are closed. When you depress the switch by hand you'll hear 2 clicks. Check functioning with your ohm meter.
Adjustment of the switch is done by turning it into the bracket until the break lights goes off.

Hth,

Rudi

 

[ginmtb]

This is interesting! That picture helps me to better understand how it works thank you!

As for the ohm meter, I put the meter on two contacts, set it to ohms, and then it worked at both stops on the switch. Boy it is very subtle the first "click".

Same result on my old switch. But I'm still glad I replaced it as there was some copper exposed and one of the PO's had tapped into the wire but then capped it.

 

[ginmtb]

Ok so I tried slightly depressing the switch still no luck. I stopped at the first click. There really isn't a second click it just bottoms. Is that an issue? Seems to be that way on my new and old switch.

 

[ginmtb]

Well crap there is a second click! And that kills my brake lights! Woohoo thanks Rudi!!!

 

[bj40green]

The first click is your brake lights coming on. When you depress the brake pedal deeper the second click comes in. This feeds 12V to your warning brake switches. If there is a pressure build up the pressure switches goes open and the warning light stays off.
If there is no pressure build up in one (or both) the switch(es) stay closed and the warning light comes on.

Step 2:
Pull the hand brake.
Turn the ign key to the on position.
Warning light should come on (telling you that the parking brake is engaged).
Step on the brake pedal.
Light should go out = GOOD (you have pressure build up)
Light stays on = Houston, we have a problem with the brake system!

Rudi

 

[ginmtb]

Thanks everyone for chiming in - as they say it takes a village, especially with these vehicles. I learn something new every day! I'm all put back together and ready to drive her to work tomorrow! Supposed to be mid-80's here in Northern CA perfect day for a ride with the top off!

 

[ginmtb]

The first click is your brake lights coming on. When you depress the brake pedal deeper the second click comes in. This feeds 12V to your warning brake switches. If there is a pressure build up the pressure switches goes open and the warning light stays off.
If there is no pressure build up in one (or both) the switch(es) stay closed and the warning light comes on.

Step 2:
Pull the hand brake.
Turn the ign key to the on position.
Warning light should come on (telling you that the parking brake is engaged).
Step on the brake pedal.
Light should go out = GOOD (you have pressure build up)
Light stays on = Houston, we have a problem with the brake system!

Rudi

This was so helpful! I don't think my light ever worked correctly since I reconnected it. Now it works exactly how you described. Pretty cool! Thanks again!

 

[Racer65]

This was so helpful! I don't think my light ever worked correctly since I reconnected it. Now it works exactly how you described. Pretty cool! Thanks again!

So what was actually the culprit? Did the old switch not give you the 2 clicks?

 

[Honger]

Wow... the content of this thread is super helpful for me. I'm not having problems with my stop lights... but my brake warning light flashes intermittently and jiggling the parking brake handle solves it. I now know exactly where to go hunting for resolution of this problem.

@bj40green , your Post #16 is pure gold for troubleshooting.

Thank you MUD!