1949 Series 61 Wiring

[49 Caddy]

  Have started replacing wiring harness for my 1949 Series 61 and have already run into issues.  Imagine that!  Anyways, I am also converting to 12 volt.  I have run the wires to the rear section of the car and have (3) on each side.  (1) for turn signal, (1) for tail/park, & (1) for reverse.  That's what is in the wiring harness.  Which one is for brake lite?  I only have (1) bulb in the tailite assembly and (2) wires to connect to it.  How does that work?  Also,  What operates the trunk lite?  Is it a mercury switch?  I'm lost.  I think my issue is I'm paying too much attention to the original wiring schematic and not really paying attention to the wiring harness and the marked wiring that comes with it.  Please advise!

[Jay Friedman]

A mercury switch operates the trunk lite.

[harry s]

The brake lights are controlled through the turn signal switch so both use the same wire. If you notice there are two contacts in the light bulb socket that mate to a double filament bulb. The brighter of the two is brake/turn signal and the other is for running lights.     Harry

[wheikkila]

If your 49 is set up like my 40. The truck light is controlled by the running lights. In changing your car to twelve volts. Be sure to change the cigarette lighter and your dimmer switch.
           Thanks Wayne 

[35-709]

I am using the original dimmer switch in my '35 12 volted Cadillac (pictured at left).  Other than an internal cleanup it has been trouble free.  6 volt switches are designed to carry a heavier load than 12 volt switches and should carry 12 volts with no problem (other than possibly age & wear).

[Joe Jensen]

You can get the 12v mercury switch and light at Bob's Automobilia:

https://bobsautomobilia.com/shop/rear-deck-items/trunk-lid-lamp-12-volt-lcl-392-12/

LCL-392-12 is the part number.  The trunk lid takes two.

Good luck!
Joe

[49 Caddy]

  Thanks for the responses.  Greatly appreciated.  I'm sure I will have more questions as I proceed.  Like I left the wiring for the turn signals in the steering column, just unplugged the pigtails.  Now have to figure which wires from the new harness go where.  Also, i have new contactor for the horn button I need to replace and there is no slack in the wire running through the column to pull out and attach the new contact to.  Gotta be a trick to it.

[harry s]

Those turn signal wires (6) are soldiered to the switch so they are a bear to change. Best to leave them as you describe as long as they are in good condition. Likewise the horn wire. There is no slack and the wire is soldiered at the base of the steering column.    Harry

[Chopper1942]

If the insulation on the OE wiring is good and there is no corrosion at the wire connectors, I would use the old wiring.  The 6V systems used heavier gauge wire than on 12V systems.  If the outer wrapping is coming off and the wires are good, get some good fabric reinforced tape (GM has some) and rewrap the harness.  One problem with the new wiring insulation is made with soy products and mice love to chew on it.