Just got brakes fixed — lights stay on!

EvilRbt

EvilRbt

Member
Joined
Aug 16, 2022
Messages
31
Location
Los Angeles
I just had my brakes fixed on my 1993 YJ. New booster and master cylinder, plus parking brake adjustment.

I pick it up and now the brake lights stay on. If I move the pedal up slightly, they go out.

Is this a fluid/pressure problem?

The mechanic insists it’s not connected to the work he did but that’s hard to believe. He suspects it’s the switch, but I can’t help feel it’s the pedal not returning as high as it needs to.

Thanks for any advice!
 
I had a similar issue on my 95 4.0/AX15.
It turned out to be a loose nut on the brake light switch. The switch mounts through a bracket with a hole in it and adjusts there. The switch closes when you push the brake peddle down and opens when depressed by the brake pedal arm.
Since this happened after a booster replacement it may be caused by the new components being a bit different.
The switch is kinda a pain to get to, but it’s probably just out of adjustment now.
 
So you don’t think it’s the pedal not returning high enough? There’s a 1/4 inch of play so if I pull the pedal back out with my toes, the lights go off.

Kinda irked the mechanic doesn’t think the issue is connected to the work he just did. It’s like, dude, you just spent a day fixing the brakes, how could it not be a related issue?!? The switch just happened to go bad at the same time. Come on. lol
 
It’s been a while, but I don’t remember seeing a spring on the pedal. But I’m getting old and forget some times.
If it was a switch problem, lifting the pedal wouldn’t turn the brake lights off.
I agree with what you said about the mechanic. He probably installed a slightly different master cylinder from the one you had and the push rod between the pedal and master cylinder is just a hair shorter. This would cause the pedal to sit slightly lower. Your switch may have been just barely working in the first place. BUT, I’d like to think a good mechanic would check the brake lights as part of the service.
 
I just read that after '91 the brake switch is adjustable. There's a plunger that turns the lights on when it extends, so when I have time later I'm going to see if I can adjust it and move the plunger in slightly, so it doesn't extend as much when the pedal is at rest.

Yeah, a bit disappointed in the mechanic. Curious if he hosed me on the cost too. New master cylinder, brake booster, and front pads $920. I can figure out most small jobs but I didn't want to mess with brakes and bleeding lines, in part bc I'm not supposed to do auto work in my apt building.
 
I understand that. Here’s a picture of the switch. There is a nut, bracket, net configuration that allows for adjustment.
IMG_7984.png
 
Adjust your brake light switch. Essentially the process is just pull the brake light switch button out too far, then let the pedal rest. Where the pedal stops will be where the switch adjusts to as “off”, then when you press the pedal any amount from that point the lights will come on.
 
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