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Light issue - Printable Version

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Light issue - neilsonnewby - 05-08-2015

Hi all. I have a 1970 Mach1, 351C 3-speed car. Well when I turn the lights on they stay on for about 20 seconds, then all of the lights turn off except the headlights. They will all turn on again if I turn the switch OFF and wait a minute then turn it ON again...then same thing. Please help

New


RE: Light issue - Steven Harris - 05-08-2015

Welcome Neilson - glad to have you check in.

Electrical is not my forte but those with that knowledge will check in directly.

The switches on these cars are prone to issues such as what you are describing. Do you know any history on you switch?



RE: Light issue - neilsonnewby - 05-08-2015

Yah, my dad left me this car and he bought it new. It has the original light switch.


RE: Light issue - Steven Harris - 05-08-2015

Congratulations - nice gift!

You may be able to clean the switch with either air, or an electrical spray cleaner and have some success.



RE: Light issue - neilsonnewby - 05-08-2015

Thank you so much....so if cleaning doesn't work im guessing that IS the problem? The grounds are fine throughout the car, like I said it is original and rust free so the grounds are clean and test good.


RE: Light issue - Mach1FatherFigure - 05-08-2015

It was not unusual in the day to incorporate a bi-metallic circuit breaker into the light switch. It would trip in over current situations. When the current stopped it would cool down until the over current heated it up again and broke the current flow.

I would guess you have a short circuit to earth somewhere. No indication where, the system was designed to get you home and prevent fires.


RE: Light issue - neilsonnewby - 05-09-2015

Thank you very much.


RE: Light issue - 1969_Mach1 - 05-10-2015

Yeah, pretty sure Mach1fatherfigure is right about the circuit breaker integrated into the light switch. Either bad switch, short to ground in the wiring, or shorted bulb(s) causing excessive current draw. For short to ground you have to visually inspect the wiring. The dash pad needs to be removed to access the upper dash wiring. But that is easy. Just a bunch of Phillips head screws, and remember the clock panel stays attached to the dash pad when removing the dash pad. If the lights will stay on long enough, look at the bulb intensities, or for dead bulbs. I've replaced several bad bulbs on cars and fixed lighting issues. Dim bulbs are bad (shorted internally) provided the wiring and grounds are good. If a bulb doesn't work, it can be bad (sometimes shorted), or the wiring in that circuit may be shorted to ground causing the problem.

I'm curious what you find.

Best Regards,
Mike


RE: Light issue - ohiomustang - 05-10-2015

Seems odd
I think the switch circuit breaker would take out the headlights too
What happens if you just pull the switch out to the parking lights?

Try unplugging the wiring to the tail lights / rear of the car.
The plugs are behind the drivers side kick panel
See if the breaker still trips
This would narrow your search for a short
Don


RE: Light issue - Steven Harris - 05-11-2015

(05-10-2015, 10:34 PM)ohiomustang Wrote: Try unplugging the wiring to the tail lights / rear of the car.
The plugs are behind the drivers side kick panel
See if the breaker still trips
This would narrow your search for a short
Don

Great suggestion Don!

Neilson, let us know how you get on and we can make suggestions from there.