brake light switch issue.

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flstf09

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After changing boosters I put the brake light switch back on the pedal.No brake lights.Went and got a new switch,still didn't work it .Finally got it to work ,came back an hour later no brake lights again.Has power coming in but power out when pedal is pressed is very sporadic .What can be  causing this?

 

midlife

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A nearly broken wire, perhaps? Check the solid green wire for the output; the green/red wire is the input side to the brake switch.

 
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I had to replace mine and had no issues. Sorry can't really help, but it sounds like what midlie said or just a bad ground.

My switch worked, but the black button on the spring was worn enough so that it took a pretty firm pedal or foot pressure to make it work. Sitting at a stoplight or checking it in my driveway, they always came on.

I had been wondering why people would run up on me & stop so close to my ass when I would slow down. Well it was cause the lights came on so late.

I thought a few times my brake lights weren't working at all, but they ALYWAYS worked! Drove me nuts that there were that many idiot drivers. Turns out it was me, I guess kinda.

When you buy a car that is supposed to be "totally" restored make sure that the little stuff hasn't been overlooked.

 

Don C

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Are the bushing and the two spacer/washers installed correctly, so the switch moves slightly back and forth on the brake pedal pin?

 
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flstf09

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I don't believe it's a wiring issue.I have my test light directly on the spade of the output.When it will sporadically light when pedal is pressed it will light brake lights.

 

flstf09

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Yes they spacers and bushing are installed correctly.It doesn't seem to me like it moves enough to make the switch break contact though.

 

midlife

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When was the last time the turn signal switch was turned on? Brake light switch output goes to the turn signal switch where it combines with each turn signal for the back lights.

 

flstf09

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A couple weeks ago would be the last time the turn signals were used.Turn signals are working fine.Everything worked fine before I changed booster.

 

midlife

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That's not what I intended to ask...when was the last time you installed a brand new turn signal switch? Maybe it went bad on you coincidentally when you changed the booster?

I'll agree with others that a booster change typically includes the push rod, which affects the brake switch itself. If when you push on the brake pedal the power from the brake light is transmitted to the turn signal switch, then the turn signal switch is indicated. If no power is transmitted, the brake switch is suspect. You'll need to pull the turn signal switch connector to make this test.

 

69 Rustang

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I have had trouble with aftermarket brake light switches. They are not as sensitive as an OE switch. A few years ago I went through a few Autozone switches before giving up and getting one from Ford. Installed OE, problem gone.

 
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I remember having to adjust the push rod when I installed a new brake booster. When I was adjusting it I got to a point where the lights were always on and the I backed it off until they went out. My lights come on as soon as I touch the brakes now.

 

rocketmans2k

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Sorry to resurrect an old thread, but I'm doing it anyway. I have power at both switch contacts with the pedal resting (not depressed) and still no lights. New master/booster, new brake light switch and new turn signal switch. Turn signals work fine as do the hazard lights, pedal travel/feel is good. One thing to note is I am missing the outer nylon spacer that goes next to the cotter pin. The reman booster I got said it had an improved bushing/spacer, so I got the impression I didn't nee the outer spacer.

Can someone help me understand how the switch works, because it doesn't seem to move at all when I depress the pedal by hand under the dash. Should I adjust the booster pushrod?

 
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rocketmans2k

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After further troubleshooting, I removed the inside spacer as nailpounder suggested, and turned out the pushrod a few turns. I can now manually depress the switch with my fingers and get the lights on, but not with the pedal. The bushing seems to be hindering pushrod travel to engage the switch. I am hesitant to simply remove the bushing and have the rod eye flop around the pedal pin. Any suggestions?

Edit: I took out the bushing and the lights work fine with light pedal pressure, so I think I'll leave it that way unless someone talks me out of it.

 
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nailpounder

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After further troubleshooting, I removed the inside spacer as nailpounder suggested, and turned out the pushrod a few turns. I can now manually depress the switch with my fingers and get the lights on, but not with the pedal. The bushing seems to be hindering pushrod travel to engage the switch. I am hesitant to simply remove the bushing and have the rod eye flop around the pedal pin. Any suggestions?

Edit: I took out the bushing and the lights work fine with light pedal pressure, so I think I'll leave it that way unless someone talks me out of it.
i don't think i have any bushings in mine  and has worked fine for almost 2 years

 

rocketmans2k

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I'm mostly concerned about wear over time, but I don't plan on driving the car a whole lot and not in hard braking conditions, so I think it will be ok. Thanks for the tip.

 

Mookie

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try to remove the spacer or spacers  i had the same problem when i added my power booster
Nailpounder. I want to thank you for your advice. Yanked my manual drums and replaced it with a Scott Drake power disc kit. Could not get the brake lights working until I pulled the bushings at your suggestion. 

 

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