brake lights stopped working

mountain33

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I had my 71 RR out last night and since Ive owned it never had to turn on the lights. Well to my suprise when leaving the show all my lights came on. Dash, headlights, tailights and side markers. It wasnt till I got home that I realized no brake lights. So today i figured i would be replacing my brake pedal switch easy fix. I checked out switch with voltage meter and have 12v through switch. At this point I have Checked all of the bulbs(good). Fuse (good) Flashers work, Blinkers work,Taillights work, Left and right directional work. Ive been working on them all day with nothing to show for my effort. The electrical schematic dosent seem to show a clear path for the power from the switch to the brake lights. the white wire goes up into steering column. From reading other post it goes into turn signal switch? At the turn switch the only terminal that has power is the pink wire on the flasher side. Should there be another power source there? Is there a schematic of the turn switch available? Thanks for taking time to look at my question. i took other peoples advice and decided to walk away cause i was losing my mind. I would of said hair but lost that years ago. Thanks
 

Thrashingcows

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All the light functions, turn signal and brake lights run through the steering column and a faulty or warped switch can cause all kinds of frustrating issues....been there! So most likely your issue is in the turn signal switch.
 

mountain33

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All the light functions, turn signal and brake lights run through the steering column and a faulty or warped switch can cause all kinds of frustrating issues....been there! So most likely your issue is in the turn signal switch.
Thanks. from what Ive seen in other post it seems like the culprit. Will dive into again tomorrow.
 

Big Bad Dad

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Maybe a dumb question, but is the physical position of the switch adjusted properly so the movement of the brake pedal makes the connection? I have seen them so far out of position that they did not work.
 

72RoadrunnerGTX

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If you have traced/verified you have brake switch voltage to the turn signal switch connector white wire and not finding this voltage at the brown and/or dark green wires in the same connector with the turn signal switch in the off position, then turn signal switch is faulty. The fact that the rear turn indicators and 4-ways are stated to be working would verify the switch is the cause.

turn signal switch.jpg
 

mountain33

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Maybe a dumb question, but is the physical position of the switch adjusted properly so the movement of the brake pedal makes the connection? I have seen them so far out of position that they did not work.
Never a dumb question. I actually had taken the brake switch out of the equation and connected the 2 wires to bypass the switch. Same results no brake lights.
 

mountain33

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If you have traced/verified you have brake switch voltage to the turn signal switch connector white wire and not finding this voltage at the brown and/or dark green wires in the same connector with the turn signal switch in the off position, then turn signal switch is faulty. The fact that the rear turn indicators and 4-ways are stated to be working would verify the switch is the cause.

View attachment 1336380
I think i finally see. I have looked at schematic hundreds of times and was not understanding how power was to get to brake light. I think the light bulb finally came on in my head. thanks for clarifying. If it wasnt dark out right now I would be going outside to work on it. I hope one day I can help somebody out on this forum.
 

PlymCrazy

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I hope one day I can help somebody out on this forum.
Just you reaching out for help is helping somebody, in fact many, on this forum. That’s much of the reason this site exists. As we share information, some from memory and others by researching behind the scenes, many of us walk away learning something new as well. As problems are solved there are many people watching a thread that never chime in. And they often are learning as a result too. Thank you and all the others who reach out and ask for help. I personally learn a lot because you reach out.

And please let us know the final resolve on this one! I have a fairly old wiring harness on mine and my turn with this issue may not be that far away LOL.
- Nick
 
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mountain33

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Just you reaching out for help is helping somebody, in fact many, on this forum. That’s much of the reason this site exists. As we share information, some from memory and others by researching behind the scenes, many of us walk away learning something new as well. As problems are solved there are many people watching a thread that never chime in. And they often are learning as a result too. Thank you and all the others who reach out and ask for help. I personally learn a lot because you reach out.

And please let us know the final resolve on this one! I have a fairly old wiring harness on mine and my turn with this issue may not be that far away LOL.
- Nick
So i figured i would keep you posted. After being motivated last night by your post. I thank you. I went out this morning and started checking out wiring going to signal switch. i found no power at the white wire terminal 1. Ive enclosed a hand drawn picture for reference. Would of loved to have done it on my laptop but dont have that much time to figure out how. The wire was also loose at terminal 1. After restoring power to terminal 1 still no brake lights. I decided to see if I could just Jump across from 1 to 4 which is the crossover power to supply power for brake lights which feeds terminal 6 on the directional side of the switch. I ran temp jumpers to verify if it would work without causing issues with the other lights. Everything works. I then soldered a jumper using #18 wire. Checked everything again back in business. I did order a replacement switch just in case but it wont get here till after the holiday. I dont think i will need it but better to have on hand just in case. One thing to note is to make sure you have a good soldered connection. My first attempt I only had 10.5 volts, Not enough to light up brake lights. Re soldered getting better connection 12.7 volts now.

IMG_20220902_152848038.jpg


IMG_20220902_114519415.jpg


IMG_20220902_115801496_HDR.jpg
 

PlymCrazy

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So i figured i would keep you posted. After being motivated last night by your post. I thank you. I went out this morning and started checking out wiring going to signal switch. i found no power at the white wire terminal 1. Ive enclosed a hand drawn picture for reference. Would of loved to have done it on my laptop but dont have that much time to figure out how. The wire was also loose at terminal 1. After restoring power to terminal 1 still no brake lights. I decided to see if I could just Jump across from 1 to 4 which is the crossover power to supply power for brake lights which feeds terminal 6 on the directional side of the switch. I ran temp jumpers to verify if it would work without causing issues with the other lights. Everything works. I then soldered a jumper using #18 wire. Checked everything again back in business. I did order a replacement switch just in case but it wont get here till after the holiday. I dont think i will need it but better to have on hand just in case. One thing to note is to make sure you have a good soldered connection. My first attempt I only had 10.5 volts, Not enough to light up brake lights. Re soldered getting better connection 12.7 volts now.

View attachment 1336776

View attachment 1336778

View attachment 1336781
That’s awesome! Thanks for the follow up and update. Great job man!
- Nick
 

72RoadrunnerGTX

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So i figured i would keep you posted. After being motivated last night by your post. I thank you. I went out this morning and started checking out wiring going to signal switch. i found no power at the white wire terminal 1. Ive enclosed a hand drawn picture for reference. Would of loved to have done it on my laptop but dont have that much time to figure out how. The wire was also loose at terminal 1. After restoring power to terminal 1 still no brake lights. I decided to see if I could just Jump across from 1 to 4 which is the crossover power to supply power for brake lights which feeds terminal 6 on the directional side of the switch. I ran temp jumpers to verify if it would work without causing issues with the other lights. Everything works. I then soldered a jumper using #18 wire. Checked everything again back in business. I did order a replacement switch just in case but it wont get here till after the holiday. I dont think i will need it but better to have on hand just in case. One thing to note is to make sure you have a good soldered connection. My first attempt I only had 10.5 volts, Not enough to light up brake lights. Re soldered getting better connection 12.7 volts now.
Are you suggesting bridging these two 4-way flasher switch terminals together is a permanent fix? There is a reason it was designed as it is. Have you tried, with key off, turn signal switch left in a turning position, with the 4-ways on yet? I see a path for the 4-way flasher voltage to backfeed through your bridge to the accessory circuit under those conditions.
Better off replacing the switch with another switch functioning as originally designed. Steer clear of all the current (yellow cam, $50) repo offerings, absolute junk.
 
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mountain33

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Are you suggesting bridging these two 4-way flasher switch terminals together is a permanent fix? There is a reason it was designed as it is. Have you tried, with key off, turn signal switch left in a turning position, with the 4-ways on yet? I see a path for the 4-way flasher voltage to backfeed through your bridge to the accessory circuit under those conditions.
Better off replacing the switch with another switch functioning as originally designed. Steer clear of all the current (yellow cam, $50) repo offerings, absolute junk.
Actually it was more of a get me thru the weekend fix with all the show s going on. i didn't want to go without brake lights. My new switch doesn't come till Tuesday. I was intrigued and i was wondering about possible back feeds also. I went out this afternoon and tried what you suggested. Didn't notice anything not acting like it shouldn't. Tried keys on, keys off and in acc. mode and nothing showed up. I even tried my radio to see if there was any issues. Only one found is its an AM radio. :) I was going to take the switch apart but considered if i screwed it up then i would be down for the weekend. I was hoping someone would get back to me considering the negative possibilities of the bridge. It seemed to easy of a fix. thanks for your concern. Will let you know if it burns up:) Think i will ck my insurance
 

i_taz

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So i figured i would keep you posted. After being motivated last night by your post. I thank you. I went out this morning and started checking out wiring going to signal switch. i found no power at the white wire terminal 1. Ive enclosed a hand drawn picture for reference. Would of loved to have done it on my laptop but dont have that much time to figure out how. The wire was also loose at terminal 1. After restoring power to terminal 1 still no brake lights. I decided to see if I could just Jump across from 1 to 4 which is the crossover power to supply power for brake lights which feeds terminal 6 on the directional side of the switch. I ran temp jumpers to verify if it would work without causing issues with the other lights. Everything works. I then soldered a jumper using #18 wire. Checked everything again back in business. I did order a replacement switch just in case but it wont get here till after the holiday. I dont think i will need it but better to have on hand just in case. One thing to note is to make sure you have a good soldered connection. My first attempt I only had 10.5 volts, Not enough to light up brake lights. Re soldered getting better connection 12.7 volts now.

View attachment 1336776

View attachment 1336778

View attachment 1336781
Save that switch, it'll probably work just fine when you cut that strap off. I just fixed mine by soldering just that 'rivet'. I tried a punch but that didn't work. I read somewhere that the heat from the brakes causes that connection to spread. It must be in nano inches because I had continuity thru the flasher switch to that rivet but not the plate underneath over to the turn signal...
 
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