1951 Caddy daily driver

[Cadman-iac]

  A quick test of your switches would be to remove one at a time and disconnect the wire, then ground that wire to see if your lights come on. The switches are just a grounding point for the courtesy lights at each individual door.
So you know that the lights are working with one of the doors, so test the other 3 by grounding your wire at the switch. Just make sure that the other doors are closed to eliminate any false results.
If grounding doesn't work for one or more of them, then you know you will have to trace the wiring back from each inoperative switch to find the fault.
Typically there is a junction or splice on that circuit where it branches out to the individual switches that can operate the lights. This will include any switch on one or more of your light housings if so equipped. This splice can corrode from water getting on it over time and I've seen them even burn apart due to this. The resistance becomes high enough to cause the wire/s to burn free from the connection.
I'm guessing that you have probably 2 dome lights, maybe more, my 56 has 2, one on each side above the doors. Plus the map light may operate with the door switches. I have my car all apart so I'm going by memory on the map light.
Hope this helps some.

Rick

 Edit: 
If you find your lights work by grounding the wire, your switch is not working. You can test each of these with a multimeter on the continuity setting with the switch out and disconnected.
 Question, did you disassemble the switches to clean them, or just clean up the contact where the wire goes?

[Mowerhoarder]

Cadman,
I did ground the wire but just to where the switch mounts, I'm starting to think that it might somehow not me grounded there? Not sure yet. I did take the switches apart to clean them and they're very clean inside so shouldn't be a problem there.

[Cadman-iac]

Cadman,
I did ground the wire but just to where the switch mounts, I'm starting to think that it might somehow not me grounded there? Not sure yet. I did take the switches apart to clean them and they're very clean inside so shouldn't be a problem there.

Try this then. Use a jumper wire to ground the wire going to the particular switch you're testing by running the jumper directly to your battery ground terminal. I believe your car has a positive ground, right?
Have you checked to see if that wire has voltage with a multimeter? If you don't have voltage, grounding it won't do anything. You would first need to determine why there isn't any voltage present in the wire, which could be a break in the wire, a bad connection at a wire splice in the harness itself where they branch out to each of the doors.
The wire does ground at the switch, but it's possible that the method used to mount the switch isn't making a good contact. I don't know how your switch is fastened, it could be with screws or some use spring steel fingers that grip the edges of the hole it goes into. If the metal around the switch or the screws is rusty that can cause the ground to not occur.
Try wire brushing the mounting points for your switch and see if it makes any difference.

Rick

[benx13]

Cool. Great model to get your hands on

[Mowerhoarder]

Cadman,
I confirmed that the switches have a good ground and that they are working as intended but I believe that the middle wire for the dome light is broken or otherwise messed up somewhere in the harness. I think I'm just gonna ignore it because the headliner is super brittle and I really don't want to break it. I'm thinking maybe the switch in the b pillar has something to do with it but not sure yet, I'm gonna grab one soon from the hardware store and throw that in and see what happens.

[Cadman-iac]

 I hope that works for you. I wouldn't want to risk damaging the headliner either, especially not knowing exactly where they spliced the ground wiring on that model. It could be just one location, or there may be multiple ones. Without striping the harness it's a crap shoot.
 Good luck.

 Rick

[Bob Kielar]

On my 55 Fleetwood the dome light only works with the rear doors and the b pillar switch. The front doors only turn on the map light that is above the radio there is also a switch on the map light so you can turn it on with the doors closed. This is the same with the b pillar switch you can turn the dome light on with all doors closed or open. To me it seems odd that the front doors do not turn on the dome light. I looked at the wiring schematics that I have and there is no mention of four door dome light or map light wiring.

Keep Cruzin,
Bob Kielar

[Mowerhoarder]

Cadman,
Yeah, I really don't want to tear up the headliner any more than it already is. If I ever do get the headliner redone I'll probably re wire it but until then, it's a small issue.

Bob,
That would make sense, I've seen some Instagram videos of a dude opening the door of a 50' caddy and the dash lights came on so maybe that's what's supposed to happen? Either way, both of my bulbs are burnt out so I'm gonna throw some new ones in and see what happens.

[Mowerhoarder]

Question/update:
I did do all 4 corners for brakes with new shoes and wheel cylinders but I'm having some trouble with the pedal feel. What's happening is the pedal will go down within 1 1/2 inches of the floor before any real braking happens but the car does stop. Once you get to that point, most of your leverage is used up but it will lock all the wheels up still, I assume it's air somewhere and I'm thinking the master cylinder as when it was sitting, all the fluid drained out and the master was dry for some time. I tried to halfass bench bleed it by just bending up some metal lines that were maybe in the fluid or maybe not in the fluid, I didn't take the master off the car but just left it on so I don't know if there's still air in it somewhere maybe? I might pull it off sometime this weekend and properly bench bleed it anyways though. I'm getting clean clear fluid to all 4 wheels with zero air which is what's making me confused. The shoes were adjusted like the manual said but I'm not entirely sure the master is adjusted properly, although it wouldn't matter if it has air in it. The brakes don't pump up or get better or worse really at all, surely it can't just be like this? 

[PHIL WHYTE CLC 14192]

Question/update:
I did do all 4 corners for brakes with new shoes and wheel cylinders but I'm having some trouble with the pedal feel. What's happening is the pedal will go down within 1 1/2 inches of the floor before any real braking happens but the car does stop. Once you get to that point, most of your leverage is used up but it will lock all the wheels up still, I assume it's air somewhere and I'm thinking the master cylinder as when it was sitting, all the fluid drained out and the master was dry for some time. I tried to halfass bench bleed it by just bending up some metal lines that were maybe in the fluid or maybe not in the fluid, I didn't take the master off the car but just left it on so I don't know if there's still air in it somewhere maybe? I might pull it off sometime this weekend and properly bench bleed it anyways though. I'm getting clean clear fluid to all 4 wheels with zero air which is what's making me confused. The shoes were adjusted like the manual said but I'm not entirely sure the master is adjusted properly, although it wouldn't matter if it has air in it. The brakes don't pump up or get better or worse really at all, surely it can't just be like this? 

Have you done the major adjustment to the brakes including adjusting the shoes with feeler gauge through the slots in the drums?

[tluke]

You need to bleed the master cylinder. If it went dry, it has air in it! Bleeding the wheels won't remove the air from the M/C. You can bleed it on the car thus removing the need to bench bleed it. Here is a video that shows using a tube from the front wheel cylinder's bleeding port back to the filler tube. Make sure it keep the filler tub full. I bench bled mine on my '55 before installing but I have done this procedure on my '57 Mark II and it works!

[dn010]

This was not necessary in 1951 with the self adjusting anchors, according to the supplemental manual.

Have you done the major adjustment to the brakes including adjusting the shoes with feeler gauge through the slots in the drums?

[PHIL WHYTE CLC 14192]

This was not necessary in 1951 with the self adjusting anchors, according to the supplemental manual.

The 1951 brakes are not self adjusting. If you do the minor adjustment you still use a feeler gauge through the slots. If the shoes are not correctly adjusted you could bleed them correctly and still have the problem you're encountering. I have a 1951 shop manual somewhere and if I find it I'll scan the brake pages and post them here. If you don't follow the manual your brakes will be useless.