1957 no brake lights unless headlights are on

[sre]

I realize my 1st mistake was buying an unfinished project. I won't go into all the setbacks to keep as short as I can. It is the brake lights not working unless the headlights are on. I have all the books, I'm trying to trace all the wires. I'm using the Ford car and Thunderbird shop manual. Ref. part 8 sect 2 lighting fig 3 and electrical manual 55,56,57. page 97 view F-G. They do not match. Also I have new parking lights NOS. the wiring color code does not correlate to either manual. Maybe I need another 6-pk. Any help would be appreciated. This isn't my 1st restoration.

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[74 Harley]

The first place to check is the brake light switch. There should be constant power at the switch.

 

[biddle]

I realize my 1st mistake was buying an unfinished project. I won't go into all the setbacks to keep as short as I can. It is the brake lights not working unless the headlights are on. I have all the books, I'm trying to trace all the wires. I'm using the Ford car and Thunderbird shop manual. Ref. part 8 sect 2 lighting fig 3 and electrical manual 55,56,57. page 97 view F-G. They do not match. Also I have new parking lights NOS. the wiring color code does not correlate to either manual. Maybe I need another 6-pk. Any help would be appreciated. This isn't my 1st restoration.

Please choose subjects that summarize what your post is about.
"1957 tbird Electrical Nightmare" could mean anything. Also, you can omit the make/model of your car from future posts. Use the search page or look at related posts below and you will see several similar topics for various years. Solution is likely the same.

 

[Ward 57]

Sounds like the brake lights are wired where the Back-up lights should be. I believe they should be wired to a constant hot terminal on the ignition switch.

 

[doug7740]

Since the brake lights only operate when the headlights are on, that tells me that you have the green wire from the stop lamp switch connected to the wrong terminal on the headlight switch. The green wire on the stop lamp switch is connected to terminal A of the headlight switch. The black/yellow wire from the parking lights connect to the junction block and then to terminal P of the headlight switch.

Attached is a diagram I made that explains where each wire should be connected on the headlamp switch.

doug7740
1955 Thunderbird Blue

 

[sre]

Yes I understand the green wire should hook up to the A terminal. I should have gone further with my diagnosious. I opened the harness from the firewall that holds the 2 wires that go to the breaklight switch. In that harness are the wires that go to the junction block on the L/side inner panel. There are 4 green /w black strip wires in that harness. down where the wires that I can terminate there is ONLY 1 green wire and it is connected to the correct wire that attachs to the turn signal switch.

 

[221239ford]

I worked on a '57 thunderbird recently that had non-working brake lights and the brake light switch was good. After chasing several other leads found out that it was a faulty turn signal flasher! Had never run into this before.

 

[Ward 57]

I worked on a '57 thunderbird recently that had non-working brake lights and the brake light switch was good. After chasing several other leads found out that it was a faulty turn signal flasher! Had never run into this before.

That's a new one to me also. I forgot that the flasher is an integral part of the circuit. They really don't fail often so tend to be forgotten.

 

[doug7740]

I worked on a '57 thunderbird recently that had non-working brake lights and the brake light switch was good. After chasing several other leads found out that it was a faulty turn signal flasher! Had never run into this before.

Now I'm confused! The turn signal flasher is part of the turn signal circuit and not a part of the stop lamp circuit. If the turn signal flasher is the cause of the brake lights not working, then explain why do the brake lights work when the headlights are on?

doug7740
1955 Thunderbird Blue

 

[Ward 57]

Now I'm confused! The turn signal flasher is part of the turn signal circuit and not a part of the stop lamp circuit. If the turn signal flasher is the cause of the brake lights not working, then explain why do the brake lights work when the headlights are on?

doug7740
1955 Thunderbird Blue

View attachment 25415

View attachment 25417

If the lights flash whether the brakes are on or not, it's not the flasher. The flasher interrupts the brake circuit when the brakes are on and feeds the bulb if the brake is off. The brake light circuit is attached to the wrong terminal on the light switch. It needs to be on a constant hot terminal.

 

[doug7740]

The flasher interrupts the brake circuit when the brakes are on and feeds the bulb if the brake is off.

Exactly, that's why I asked if the flasher is the cause, why do the brake lights work when the headlights are on?

doug7740
1955 Thunderbird Blue

 

[Ward 57]

Exactly, that's why I asked if the flasher is the cause, why do the brake lights work when the headlights are on?

doug7740
1955 Thunderbird Blue

The green wire needs to go to a constant hot terminal. Most likely the terminal on the switch which is getting constant power from the battery.

 

[doug7740]

The green wire needs to go to a constant hot terminal. Most likely the terminal on the switch which is getting constant power from the battery.

That's why I said that the green wire on the stop lamp switch is connected to terminal A of the headlight switch. But since sre said that the green wire is hooked up to the A terminal, what would happen if the circuit breaker inside the headlight switch was always open? Is it possable that when the headlights are switched on that the circuit is being back fed through the second internal circuit breaker allowing current to flow to the stop light circuit? Maybe a defective headlight switch is the cause.

doug7740
1955 Thunderbird Blue

 

[cokefirst]

I realize my 1st mistake was buying an unfinished project. I won't go into all the setbacks to keep as short as I can. It is the brake lights not working unless the headlights are on. I have all the books, I'm trying to trace all the wires. I'm using the Ford car and Thunderbird shop manual. Ref. part 8 sect 2 lighting fig 3 and electrical manual 55,56,57. page 97 view F-G. They do not match. Also I have new parking lights NOS. the wiring color code does not correlate to either manual. Maybe I need another 6-pk. Any help would be appreciated. This isn't my 1st restoration.

The brake lights should be wired to an always hot connection under the dash You will see the wires that go to the brake light switch. One of those wires should be hot at all times. That wire is not connected to the proper power source. The other wire goes from the switch into the turn signal wiring so that when one side is activated through the turn signal switch, the other side will still light up when the brakes are activated.

You say that the color code does not match the colors in the electrical manual. I have the manuals, but the ones I own are separate for the three years and are not combined into one manual. If the colors do not match, is is possible that someone purchased a universal harness from a place like EZ wire? Those after market wiring sets will have a fuse panel that was not on the original factory wiring. The original factory wiring will have inline fuse in the system. Dan

 

[sre]

Well I tried replacing the flasher, that didn't work. I actually have 2 harnesses from the guy. The one in the car is an original Ford harness, it has all the OE ends on the wire. I also have the 55, 56, 57 wiring diagram book. Each year is separated from the other. I also have a 57 Ford shop manual. These 2 manuals show some different color codes. I took some pictures today, not great but it may help. 1st there is no junction block under the dash. I bought the correct one. Here's one problem. There are 6 wires from the turn signal switch all have male ends. There is a group of 6 wires coming from the engine comp. that go to the L/H inner fender and those 6 wires have female ends on. HELP! please

 

[doug7740]

Looking at the picture of your headlight switch, I don't see any wires connected to terminal A. The green wire for the stop lamp switch and the blue/black wire for the clock are connected to terminal A.

doug7740
1955 Thunderbird Blue

 

[sre]

The double green wire is attached. It slides down on a pin. There is also another wire on a pin right behind the green wire. You can see it on IMG 0244. My switch has 7 connections, from looking at yours there is 6, unless one is hidden.

Also your switch looks original mine is new in the box. That may have something to do with the way they are made.

 

[doug7740]

Looking at IMG 0244, I see the double green/yellow wires for the door jamb switches and they look like they are attached to terminal A. They should be attached to terminal D.

It looks like the black wire for the tail and license lamps is attached to terminal D. It should be attached to terminal R.

It looks like the green wire for the stop lamp switch and the blue/black for the clock is attached to terminal R. They should be attached to terminal A.



Look over the Headlight Switch Terminals diagram that I attached earlier and attached the wires to the correct terminals.

My headlight switch does have 7 terminals, but in the picture you can't see terminal I because it is hidden behind the red/yellow wire that is attached to terminal H.

doug7740
1955 Thunderbird Blue

 

[sre]

Thank you I will change them 1st thing in the morning. I'll let you know, again thanks.

 

[sre]

Well that didn't work. The blue/green wire when attached to terminal A the brake lights work but the parking lights are on all the time. I thought I could cheat no that didn't work. When I hooked a hot wire to either one of the green wires that go down to the switch the brake lights come on and do not go out until I unhook the hot wire.