Electrical Brake Light Switch Help

[joeyhinderberger]

Anyone have experience replacing a brake light switch, without removing the dash and/or steering column. it seems impossible to access otherwise but i watched a youtube video of a guy with a CJ7 and he explained how he did it but didn’t really show. just curious of what you guys think. can it be done without disassembling a bunch of things?

Thanks!

 

[TSB8C]

Yes. I changed mine when I did the engine/tranny swap. I needed a dual switch to do not just the brakes, but also control the lockup torque converter. S I now have a switch assembly with one NO switch that closes when activated and one NC switch that opens when activated all in one switch assembly. The NO closes and turns on the brake lights and the NC opens and disconnects power to the tranny to deactivate the torque converter lockup function. I did not remove the dash or the pedals when replacing the switch.

It was indeed a pain, hard to access, required contortionist moves, but I felt easier than removing the entire dash or the pedal assembly to do it. After removing the wire connector plug, I used a large flat blade screwdriver to push the switch up and out of the metal clip that holds it in the bracket. I did not try to rotate and unscrew it out since there was such Limited space to rotate it and no real good way to grip it while trying to turn it. It is threaded and can be screwed in/out of the clip, but it can also just be pushed/pried out easier I felt. I then inserted the new one in the same way, just pushed/forced it into the clip. Once in place, I used a small pliers to slightly bend the "tab" in the pedal to adjust how far the pedal moved before activating the switch.

 

[CJ]

So much good information...

 

[joeyhinderberger]

Yes. I changed mine when I did the engine/tranny swap. I needed a dual switch to do not just the brakes, but also control the lockup torque converter. S I now have a switch assembly with one NO switch that closes when activated and one NC switch that opens when activated all in one switch assembly. The NO closes and turns on the brake lights and the NC opens and disconnects power to the tranny to deactivate the torque converter lockup function. I did not remove the dash or the pedals when replacing the switch.

It was indeed a pain, hard to access, required contortionist moves, but I felt easier than removing the entire dash or the pedal assembly to do it. After removing the wire connector plug, I used a large flat blade screwdriver to push the switch up and out of the metal clip that holds it in the bracket. I did not try to rotate and unscrew it out since there was such limited space to rotate it and no real good way to grip it while trying to turn it. It is threaded and can be screwed in/out of the clip, but it can also just be pushed/pried out easier I felt. I then inserted the new one and the same way, just pushed/forced it into the clip. Once in place, I used a small pliers to slightly bend the "tab" in the pedal to adjust how far the pedal moved before activating the switch.

thanks for responding. your description. of how you you removed it is much like the video i saw. essentially he took really long pliers and pried it out.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

but it sounds like a PITA as much as i think it will be!! just hope that this is my problem and it’s all worth it!!

 

[joeyhinderberger]

One last question, did you remove the driver seat out to get better access? or were you able to do all of that with the seat in place?

 

[TSB8C]

Didn't remove the seat. Just got up under there and did it. Yes, PITA - but not as bad as removing seat, dash, pedals, etc and then having to put them all back in afterward.

 

[joeyhinderberger]

Thanks, i appreciate the feedback!

 

[TSB8C]

A few tests to make sure your switch is actually bad may be worth doing before going through all that trouble. Has the switch perhaps moved a bit (pushed back in the clip such that the "tab" on the pedal is no longer pushing it in far enough? Check this by using a small flat blade screwdriver and just push the plunger and see if the brake lights come one. Can also jump around the switch by removing the wire connector and inserting a bent paperclip to touch the contacts and see if the brake lights come on. Your brake light circuit also goes through the turn signal switch in the column. Do the rear blinkers work OK even though the brake lights are an issue? Same light of course (blinker and turn signal) - just the turn signal switch separates the +12 signal when a blinker is turned on while the brake is pushed. Here's a very simplified diagram, not including the turn signal portion of the circuit.


And here's the wires to check with your meter or test light.

 

[joeyhinderberger]

Thanks for this info...so funny you should bring up the blinkers. They are not right at all. and have not been for some time. The driver side blinker works fine (with and without the headlight switch turned on). The passenger side blinker does "work" but it also feeds back to the driver side, so both blinkers are on when turning on the passenger side blinker. Now, when the headlights are turned on, the passenger blinker doesn't work at all. In this case, i wonder if i replace the turn signal switch (which sounds easier to do) is the answer?

The wiring harness you show in your picture, this is the wiring harness on the steering column, correct?

I just checked the power source at the tail light and when the brake pedal is depressed, no power is reaching the tail light.

 

[TSB8C]

No power at the white wire in that pic is a sign your brake light switch is indeed bad. Not 100% conclusive as you would need to verify +12 going to the switch from the fuse block, but a good sign you're on the right path with suspecting the brake light switch itself.

When one blinker "feeds back" to the other, that is a good sign of a bad ground. Your tail lights are grounded via the mounting bolts to the body. These are common to be bad with rust, corrosion, etc. I ran dedicated ground wires from my tail lights rather than just rely on the mounting bolts to the body.

 

[joeyhinderberger]

Okay, so i back probed the connector using a sewing needle since my test light was too thick to get into the connector. With the brake depressed, no voltage was reading. I tried to test the other wires to see if i was getting any voltage since i know the blinkers were getting power, but even those didn't get any reading...so i decided that it would be best to disconnect the power supply to the brake light switch and test the continuity on the brake light switch. To my surprise, there was continuity so i think the brake light switch is good, and what i really have is a power problem.

If that is correct, then it looks as if i need to replace the turn signal switch. Let me know if there is another way to do the back probing to prove out its power issue.

Thanks!!

 

[TSB8C]

Since you now believe it's a power problem, check the power from the fuse block. There is a fuse for "HAZ / STOP" that supplies the +12 to the brake light switch. This is a red with white stripe wire. This same source also goes to one terminal in the fuse block for the hazard flasher unit. So you can check there for +12 as well. Then coming from the other terminal on the brake light switch and going to the connector for the turn signal switch is a light green with red stripe wire. So you should always have +12 on the red with white stripe going from the fuse block to the brake light switch and to the hazard flasher socket. Then you should get +12 on the light green with red stripe on the brake light switch and going to the turn signal switch connector when the plunger on the brake light switch is depressed. Blinker power comes from another source. It is possible to have blinkers and no brake lights, even though technically it's the same lights, due to different paths the +12 comes in on. Remember, blinkers require key on while brakes and hazards don't - hence why different power sources are needed. All that magic happens in the turn signal switch in the column.

 

[joeyhinderberger]

Here's what I am trying now. I have confirmed that it is a power source issue coming from the fuse box. I have decided to run a fresh hot wire from the fuse box using a fuse tap and feeding the switch that way. I did a test of this using doing a "jump" directly from the fuse to the brake light switch and my brake lights lit up. I then ran my test light on the Harness and nothing, no power, which further confirmed the power issue. I will let the board know what the result was after I try this.

 

[TSB8C]

So now you know for 100% sure you don't need to struggle changing that brake light switch. Yea...