Brake Lights Stopped Working-77 New Yorker

77newyorker440

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Hey guys, sorry about the volume of posts, lately, I have just been barreling through a couple of car projects recently due to the nice weather.
The other day, my dad and I finished cleaning the passenger side of the engine block, the oil pan, the bottom of the transmission, and we also put a new speedometer cable in (goes from the transmission to the cruise control).

Started it up later that day and had no brake lights.

The only things that happened between the loss of brake lights and having brake lights the day before were the cleaning and one hard slam on the brakes that jostled the car a bit. What could have affected the lights?

Here is what I know so far:
1. I tested all the fuses and all showed about 10 ohms of resistance.
2. I cannot find any switch for a New Yorker that has cruise control, all of them say that they are made for cars without cruise control (wasn't that a standard option on the New Yorker?)
3. I cannot even see the current switch on the car when looking under the dash, it must be pretty high up in there.
4. The tail lights work with the parking lights and with the headlights, but they show nothing when the brakes are depressed.
5. There is one super beat wire running near the transmission and then into a plug that looks like it runs into the lean burn, but I am not sure.

What should I do? Attached below is a picture of the stoplight/turning signal/hazard wiring diagram:

chrysler brake light map.jpg
 
The brake light switch can't be too high up under the dash. You should be able to see it since it releases the switch button when you push down on the pedal. Seems to me it should be about 2/3rd the way up the pedal. Sounds like maybe that switch failed and the button stays in.
 
This is a generic drawing of a brake light switch so you can look for it on your car, unless as @300rag pointed out and you also lost hazard and turn signals.

upload_2020-10-2_18-13-46.png
 
I tested all the fuses and all showed about 10 ohms of resistance.

Shouldn't be any resistance across any of the fuses. Something is wrong... possibly with how you are checking them. Fuses are either good or not, so checking them is more about continuity across the fuse or not.

You are really just concerned with the brake light fuse. Pull the fuse and just look at it. A 20 amp fuse can easily be seen if it's blown or not. If it looks good, test for continuity and if it really does measure 10 ohms resistance, toss it and put a new one in. If it looks good, test for voltage and that will tell you if it's a feed problem or if the issue is farther down the line. If no voltage, look at the back of the fuse block.

Since you ran a new speedo cable up under the dash, my first suspicion would be that you knocked something loose under the dash. Check the connections at the brake switch and the large plug under the steering column.
 
Shouldn't be any resistance across any of the fuses. Something is wrong... possibly with how you are checking them. Fuses are either good or not, so checking them is more about continuity across the fuse or not.

You are really just concerned with the brake light fuse. Pull the fuse and just look at it. A 20 amp fuse can easily be seen if it's blown or not. If it looks good, test for continuity and if it really does measure 10 ohms resistance, toss it and put a new one in. If it looks good, test for voltage and that will tell you if it's a feed problem or if the issue is farther down the line. If no voltage, look at the back of the fuse block.

Since you ran a new speedo cable up under the dash, my first suspicion would be that you knocked something loose under the dash. Check the connections at the brake switch and the large plug under the steering column.
Okay, I was looking back at the multimeter and I realized that I read it wrong, it is really just about 1 ohm of resistance.

The speedo cable I ran goes from the cruise control unit in the engine bay so I don't think it affected anything unless it messed something up in the cruise control which has some vague relation to the brake light circuit that I do not understand.

Thanks for all of the suggestions, I will do a voltage test tomorrow on the fuses tomorrow, but my main guess is that the switch is bad since the turning signals work, as well as the taillights when the car is in
Thanks,
77newyorker440
 
The brake light switch can't be too high up under the dash. You should be able to see it since it releases the switch button when you push down on the pedal. Seems to me it should be about 2/3rd the way up the pedal. Sounds like maybe that switch failed and the button stays in.
Okay, I will check again and see if I can find it, I probably just missed it. However, one issue that Im gonna run into is finding a new switch if that one is bad, since I cannot find one site that lists a brake switch for a car with cruise control, so if anyone has any suggestions on where to look, that would be really helpful
Thanks,
77newyorker440
 
Okay, I will check again and see if I can find it, I probably just missed it. However, one issue that Im gonna run into is finding a new switch if that one is bad, since I cannot find one site that lists a brake switch for a car with cruise control, so if anyone has any suggestions on where to look, that would be really helpful
Thanks,
77newyorker440
If you need a new switch, you can use one from a newer Chrysler product up thru 1989. The systems operate the same way, but you may need to splice in new connectors.
 
OK, if I may have my few minutes here as I probably been cursed too often with bad Formal brake light switches.
First of all, I pity you.
Secondly, 74-78 brake light switches with Cruise Control are still out there but are getting harder to find. Easiest way to find one is to Google the part number in quotes. Sorry, I no longer have my Parts Manuals so you'll have to find it yourself. Please buy a Parts Manual, regardless.
The worst part of this is replacing the switch. Good luck if you don't have small hands and long spindly fingers.
medicine-bandage-with-very-bloody-red-injury-man-hand-after-accident-2A5Y52N.jpg


That damn switch is almost inaccessible.
 
When I had to change the switch on my many formals, I always dropped the lower dash panel. Not hard, just a lot of screws.
 
Okay, I was looking back at the multimeter and I realized that I read it wrong, it is really just about 1 ohm of resistance.

The speedo cable I ran goes from the cruise control unit in the engine bay so I don't think it affected anything unless it messed something up in the cruise control which has some vague relation to the brake light circuit that I do not understand.

Thanks for all of the suggestions, I will do a voltage test tomorrow on the fuses tomorrow, but my main guess is that the switch is bad since the turning signals work, as well as the taillights when the car is in
Thanks,
77newyorker440
If you were working under the dash it is possible that you knocked a wire off the switch. Wouldn’t be the first time this happened.
 
Hey Guys, it has been a while but the switch was finally replaced today, you guys were correct, very easy to see. However, the new switch has had no effect on the brake lights, as they still do not work. Other than a break in the wiring, is there anything else that could cause this absence of brake lights on both the driver and passenger side?
Thanks,
77newyorker440
 
You should have a pink and white wire at the switch. Check with a test light to see if the pink is good, (power from fuse box), if so, press on the brake pedal and see if the white wire lights, If not you still have a bad switch, and if so it is between the brake switch and the turn signal switch.
 
If you were working under the dash it is possible that you knocked a wire off the switch. Wouldn’t be the first time this happened.
Yep. I knocked mine loose while replacing the carpet. I was in the middle of Woodward during the Dream Cruise when it was brought to my attention. Fixed it in two minutes in an AutoZone parking lot!
 
You should have a pink and white wire at the switch. Check with a test light to see if the pink is good, (power from fuse box), if so, press on the brake pedal and see if the white wire lights, If not you still have a bad switch, and if so it is between the brake switch and the turn signal switch.
I believe I have a yellow wire and a red wire
 
At the rear of the switch, (if you have cruise control). If it is red, that is the one from the fuse box, and the other feeds to the turn signal switch.
Just tested it, no power going coming through the red wire as far as I can tell. The fuse also does not appear to be blown, plus the Key-In Buzzer works, however it is the only thing on that fuse that does work (most of the other stuff not working is likely due to bad bulbs and switches though). What is connected to that red wire?
Thanks,
77newyorker440
 
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