1957 no brake lights unless headlights are on

[Ward 57]

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.

Once you get it sorted, spray some PB Blaster on the rheostat coils and your dash lights will work and be adjustable. They tend to crud up and people have replaced the whole switch for this simple fix.

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[doug7740]

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.

During our conversation I have attached 4 different wiring diagrams and there is no blue/green wire at the headlight switch on any of the diagrams. I’m beginning to think that cokefirst was correct in saying that someone purchased a universal harness and it is not like the original factory wiring.




Looking at the wiring diagram:

The blue wire with the red band (BL-R) is connected to the “I” terminal of the headlight switch and controls all of the instrument panel lamps.

The red wire with the yellow band (R-Y) is connected to the “H” terminal of the headlight switch and goes to the dimmer switch for the high beams.

The black wire with the yellow band (B-Y) is connected to the “P” terminal of the headlight switch and goes through the front junction block to the both front parking/turn signal lamps.

The blue wire with the black band (BL-B) is connected to the “A” terminal of the headlight switch and goes through the 3 amp fuse to the clock.

The green wire (G) is connected to the “A” terminal of the headlight switch and goes to the stop lamp switch.

The green wire with the yellow band (G-Y) is connected through the 7.5 amp fuse to the “D” terminal of the headlight switch and goes to the left door jamb switch.

The black wire (B) is connected to the “R” terminal of the headlight switch and goes to both rear turn signal tail & stop lamps and the license lamps.

The yellow wire (Y) is connected to the “B” terminal of the headlight switch and comes from the starter relay.

The yellow wire (Y) is connected to the “B” terminal of the headlight switch and goes to the “B” terminal of the ignition switch.

The blue wire with the white band (BL-W) is connected to the “B” terminal of the headlight switch and goes to the cigar lighter.

Unless you can attach clear pictures of your headlight switch and all of the wires that are supposed to connect to it, I don’t think that there anything else I can do to help you.

doug7740
1955 Thunderbird Blue

 

[sre]

Doug in one of my pictures, the one you made comments about moving the wires I was unclear about the B/G wire. It is actually a blue wire and a green wire ajoined to the one connector. I think I am finally understanding what I am working with. The man that previously owned the car took the original harness apart, then fabricated his own harness. That is what caused all my problems. I found in Casco's part's manual a picture of the wiring harness that goes from the turn signal switch to the junction block that isn't in the car. The man eliminated the junction block and with new female connected those wires together. Also I looked on ebay for a used harness, that's when I saw how the harness was made. That convinced me this guy put the harness together. I will take more pic. tomorrow hopefully they are better. Again thanks a lot for your help

 

[Ward 57]

Doug in one of my pictures, the one you made comments about moving the wires I was unclear about the B/G wire. It is actually a blue wire and a green wire ajoined to the one connector. I think I am finally understanding what I am working with. The man that previously owned the car took the original harness apart, then fabricated his own harness. That is what caused all my problems. I found in Casco's part's manual a picture of the wiring harness that goes from the turn signal switch to the junction block that isn't in the car. The man eliminated the junction block and with new female connected those wires together. Also I looked on ebay for a used harness, that's when I saw how the harness was made. That convinced me this guy put the harness together. I will take more pic. tomorrow hopefully they are better. Again thanks a lot for your help

Don't you just marvel at these shade tree mechanics that have no idea on how an automotive wire harness works?
I've watched so many shows on Motor Trend from Garage Squad to full restoration shops that have to start from scratch on the wire harness. I do feel your frustration. Thank goodness mine has not been messed with but dealing with old hard wires is an other situation.