1957 Turn Signal Indicator Light Circuit
#1
1957 Turn Signal Indicator Light Circuit
I finally got my front bumper reattached and hooked up the turn signal lights to find that, while the signal lights function correctly, both dash panel indicator lights flash regardless of the direction selected (kind of like hazard lights).
The wiring harness is new and correctly oriented. There is a Bussman 550 three prong flasher unit.
The wiring diagram below shows the indicator lights (T.S. Pilot Lamps) are fed by common feed from the "P" prong from the flasher unit. The LEFT indicator light also receives a feed from the RIGHT turn signal circuit. Similarly, the RIGHT indicator light is attached to the LEFT turn signal circuit.
Since there is no defined ground for the indicator lights other than at the signal light, I am assuming the ground is supposed to occur through the non-selected side.
The indicator lights are attached to a pretty basic printed circuit board on the dash panel and I have checked to see that there are no ground leaks on the board.
Seems like an overly complicated set up but it must have worked correctly at some point.....
I have ordered the correct NOS Tung Sol Flasher for the car and am hoping that will provide the solution but I have my doubts.
Any suggestions appreciated,
Bill
The wiring harness is new and correctly oriented. There is a Bussman 550 three prong flasher unit.
The wiring diagram below shows the indicator lights (T.S. Pilot Lamps) are fed by common feed from the "P" prong from the flasher unit. The LEFT indicator light also receives a feed from the RIGHT turn signal circuit. Similarly, the RIGHT indicator light is attached to the LEFT turn signal circuit.
Since there is no defined ground for the indicator lights other than at the signal light, I am assuming the ground is supposed to occur through the non-selected side.
The indicator lights are attached to a pretty basic printed circuit board on the dash panel and I have checked to see that there are no ground leaks on the board.
Seems like an overly complicated set up but it must have worked correctly at some point.....
I have ordered the correct NOS Tung Sol Flasher for the car and am hoping that will provide the solution but I have my doubts.
Any suggestions appreciated,
Bill
#2
Bill, A bad ground was the first thing that crossed my mind. Bad or loose or dirty grounds,,,,,,,,,and things really get weird when the electrical path is disruppted. You say both dash lights are blink at the same time,,,,,,,,and what are the outside turn signal lights doing? Do they blink normal left and then right? Just curious if you removed and then reinstalled the two dash turn signal bulbs from their sockets? I had two dash lights that would not light but rotated them a couple of times in their sockets and magic. They worked. Also, i assume you unplugged the turn signal wiring for each light at the radiator cross bar piece. I believe blue and white are the colors, and if so did they get plugged back in the proper plug.?
#3
I had this same problem with my '56 years ago. Both dash indicators would flash regardless of the direction indicated. Finally, I bought a Tung Sol P-273-D, and it solved the problem. DO NOT use a 550.
#5
Bill, A bad ground was the first thing that crossed my mind. Bad or loose or dirty grounds,,,,,,,,,and things really get weird when the electrical path is disruppted. You say both dash lights are blink at the same time,,,,,,,,and what are the outside turn signal lights doing? Do they blink normal left and then right? Just curious if you removed and then reinstalled the two dash turn signal bulbs from their sockets? I had two dash lights that would not light but rotated them a couple of times in their sockets and magic. They worked. Also, i assume you unplugged the turn signal wiring for each light at the radiator cross bar piece. I believe blue and white are the colors, and if so did they get plugged back in the proper plug.?
I was thinking it has to be a bad ground somewhere so I've double ( triple!) checked everywhere, especially where the indicator light screw into the dash since that's the only part of the whole system that's not new. I've been under the dash so many times in recent days that my back and neck are now permanently curved the wrong way....
The turn signals themselves work as they should. I'm not sure the indicator lights worked when I got the car as I basically bought the car and then started taking it apart.
Bill
#6
I found one on eBay and it should be here any day. I'll report back after I install it.
Thanks
Bill
#11
Thanks!
I literally just put on the last part (the rear view mirror) before it heads to the interior shop.
It has been a six year process that I have been documenting over on the Major Builds section.
I’ll have the final installment up soon.
Bill
I literally just put on the last part (the rear view mirror) before it heads to the interior shop.
It has been a six year process that I have been documenting over on the Major Builds section.
I’ll have the final installment up soon.
Bill
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September 24th, 2017 12:56 PM