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1939 Buick Special light switch wiring


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Hello again from Norfolk VA.

Time to sort out the wiring from the light switch and the dimmer switch to all the bulbs at the front of the car. I have a shop manual with which to validate connections. But I find the shop manual lacking in describing which light switch terminals are supposed to be energized at the three light switch positions. Has someone out there created or ran across a chart of some kind that matches switch positions with energized switch terminals?

 

Thank you,

Kevin

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Thank you Mr. Painter.

Pretty sure I have the original switch.

Tried all the combinations of light and dimmer switch positions - never got a voltage at the bulb inputs in 'city'.

Cut all three wires to the dimmer switch. Makes sense to me that zero ohms should be found somewhere between those wires.

Nope, dimmer switch wires are all open to each other.

Time to order a replacement dimmer switch.

Thank you again for your reply.

R,

Kevin

 

 

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The switch itself could be worn out.  I went through 3 before finding a good one.  I found a NOS on eBay.  Wear and tear makes the switch contacts spotty at best in the different positions.

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Thank you Mr. 39BuickEight.

 

While I'm "there" it does make sense to replace both switches.

The pull switch middle position, I have to wiggle a bit before the tail lights come on.

I haven't yet replaced either the light or dimmer switches.

Having enjoyed observing your hard-earned restoration, is the dimmer switch replaced from under the car or inside?

 

Thx!

Kevin

 

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Some headlight switches can be CAREFULLY dis-assembled and cleaned. Another possibility is to use aerosol contact cleaner and spray it into the switch mechanism while operating the switch through all positions with the battery disconnected. 

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On 4/26/2020 at 12:30 PM, 39Cdan said:

Hello again from Norfolk VA.

Time to sort out the wiring from the light switch and the dimmer switch to all the bulbs at the front of the car. I have a shop manual with which to validate connections. But I find the shop manual lacking in describing which light switch terminals are supposed to be energized at the three light switch positions. Has someone out there created or ran across a chart of some kind that matches switch positions with energized switch terminals?

 

Thank you,

Kevin

 

 

I don't recommend thinking about it like that. It isn't quite like that. Circuits snake in and out of the headlight switch on multibeam systems, and worse, theres more than one kind. I believe in 39 its 1) off 2) park 3) dimmer switch dims right and left lights 4) dimmer switch dims the right light ONLY.

 

Don't take my word though, check the book.

 

The dimmer switch is just a single-pole double-throw switch. You can check it's basic function with an ohmmeter or continuity tester. One terminal, probably in the center, is connected to a second terminal. Kick the switch and it will connect the center to a third terminal, disconnecting the second one.

 

If you could post the wiring diagram (I have not seen the 1939 wiring diagram Online), and also post exactly what functions don't work, I might be able to come up with some idea about how to test it.

 

 

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Good Morning!

 

This time I refused to be outsmarted by an 80 year old car part (although having typed that I've really set myself up) :)

Yes Sir, the middle on-position of the light switch causes current to come back to the light switch and pass from one terminal to another, per the attached (Low beam 7 to 6, Hi beam 5 to 4).

 

The dimmer switch I completely cut away from the harness wiring and ohm'd all combinations of switch settings and terminals - open circuit in every config. - replacement switch on order.

So, who can school me on replacing the dimmer switch?

 

Thank you,

Kevin1975048202_39SpecialLtSw.thumb.png.d8552399dfc06c153726569174da5fca.png

 

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