1950s Dome light switch not working

[Daffer]

Hey everyone I'm hoping someone can help me with this problem, my dome light switch in my 1950 cadillac series 62 stopped working when I open the back doors it turns on but when I use the interior switch nothing! I tried turning the bulb thinking maybe one cobtact is burnt out since its double contact signal filament but nothing! What could be the problem or how can I figure this one out? Thank you

-Joshua

[Michael Petti]

I'd look at the headlight switch. If it's like my 60, and I think it is, there is a contact when you turn the knob all the way to the left. If it is  corroded or damaged your lights won't work.  Also check the wiring contacts to the switch.  They can be Corroded too, and a good cleaning could fix it. I hope this helps.

[Cadman-iac]

Hey everyone I'm hoping someone can help me with this problem, my dome light switch in my 1950 cadillac series 62 stopped working when I open the back doors it turns on but when I use the interior switch nothing! I tried turning the bulb thinking maybe one cobtact is burnt out since its double contact signal filament but nothing! What could be the problem or how can I figure this one out? Thank you

-Joshua

Someone else was just going through this very same problem on a 51 I think it was.
Anyway, if the light comes on with any of your switches, then it's got power to the bulb, the bulb is good, and at least one of those switches is good.
Your switches are the ground circuit for the courtesy lights. If one, or more, is inoperative, you need to check to see if you have voltage at the switch, and if so, try grounding the wire. The light should come on. If it does, then it's the switch that needs attention, either cleaning or replacing.
If you do not have voltage at the switch, then your wire is not connected at some point in the circuit, usually its at a junction where multiple wires are tied together where they branch out to the individual switches. Most of these junctions are in the middle of this harness along the floor, but you should look at the schematic for your vehicle to see if it indicates where exactly that might be.
What may have happened is water has gotten into the harness somehow and the connection/junction has corroded, and the current will cause the wire to burn in half. The corrosion causes resistance and that will eventually cause you problems.

Then for the headlight switch, do as Michael mentioned and you should find the fault.

Good luck with your car, I hope you locate the problem.

Rick

[tluke]

As Rick wrote if the dome light works ever, it has power to it. The dome light has one power line to it. To turn it on, it has ground wires going to each door jam switch and to the switch on the B-pillar. If any (or all) of those switches complete the ground, the light goes on. If the light goes on with each of both back doors opening, the culprit is likely that switch on the B-pillar Those B-pillar switches are notorious for going bad. When I first got my '55 Series 75 that switch (plus the two on the C-post on my limo) were all non-functional. I took the switch out and took it apart and cleaned all the contacts and when reinstalled it worked, but I had to move the switch to just the right position for the light to come on. A second more thorough cleaning and adjustments made it more consistent. The switch itself is grounded to the car's body through the screws that hold it to the B-pillar so you may have to clean up those screws or the screw holes in the b-pillar behind the interior fabric to complete the ground. As Rick says, you should have power to the wire to the on/off switch at all times (multimeter lead to the wire [black in my car] on the switch and other lead touching a clean metal surface on the body somewhere). If no power, then the ground wire from the dome light to the switch is bad.

Not sure about the '50 Cad, but on my '55 the headlight switch is NOT used to turn on the dome light but the dome light power comes off the headlight switch. So a short in that line from the headlight switch to the dome light would trip the thermal breaker in  the HL Switch and turn the dome light off (and clock and map light etc) but it would come back on when the breaker cooled (and then off again from the short etc etc).

[Daffer]

As Rick wrote if the dome light works ever, it has power to it. The dome light has one power line to it. To turn it on, it has ground wires going to each door jam switch and to the switch on the B-pillar. If any (or all) of those switches complete the ground, the light goes on. If the light goes on with each of both back doors opening, the culprit is likely that switch on the B-pillar Those B-pillar switches are notorious for going bad. When I first got my '55 Series 75 that switch (plus the two on the C-post on my limo) were all non-functional. I took the switch out and took it apart and cleaned all the contacts and when reinstalled it worked, but I had to move the switch to just the right position for the light to come on. A second more thorough cleaning and adjustments made it more consistent. The switch itself is grounded to the car's body through the screws that hold it to the B-pillar so you may have to clean up those screws or the screw holes in the b-pillar behind the interior fabric to complete the ground...

I tried taking the switch off saw nothing wrong so I screwed it back on and I'm assuming it might have been the ground screws to the b-piller as after re-screwing it to the piller it worked! Thank you for the help!
-Josh

[Cadman-iac]

 Glad you found the problem and it was an easy fix.
 
   Rick