35 Buick dome light question

[Buick35]

On my 35 Buick sedan the dome light works but if I open the front passenger side door(the side the switch is on) it goes out.I don't think that's normal.Please correct me if I'm wrong.It just has the one pillar switch.Thanks.

[Buick35]

Somehow with the door open(it only happens on that door) it creates an open circuit. I ran a wire from the open door frame to the body and the light works. I'll connect a small ground wire between them and it should be o.k.

[Grimy]

Can't remember how it was on my long-gone 1934 56S, but consider that wood-framed bodies originally came with two-wire switches for dome lights and courtesy lights: one wire was the power, the other was to ground because the wood framing interrupts the ground path.

 

In recent years, auto supply stores have not offered switches with more than one wire (power), because all-steel bodies don't need a ground post.

[Buick35]

I thought I had the dome light problem fixed by installing a ground between the car body and the door but I still couldn't get the dome light to work with the door open. Any suggestions? Is there a place to ground the body to make it work? The light works with the three other doors open or closed.Wierd,I know.Thanks

[JACK M]

Typically, the door switch supplies the ground when you open the door.

Power at the dome light is constant.

[Buick35]

My car doesn't have door plungers,just a switch,Thanks.

[Oldtech]

I'm guessing the ground you tried just wasn't connected. The door post may not be the only thing ungrounded, the whole body may not be connecting except with the door closed. Try some other locations like on the frame or transmission. 

[Buick35]

Thanks,I'll try grounding the frame to the body.I dont know why it's only a problem on the passenger front door.

[Grimy]

My second-handiest electrical diagnostic tool (behind a VOM, of course) for 6V systems is a 6-foot length of 10-gauge wire with alligator clips on each end.  Or even TWO of them.  Use one or more to establish a temporary ground to see if that's the problem.  In your case, I'd initially ground the light socket body to the frame with a jumper.  And probably add a body-to-frame woven strap where it won't be seen, just on general principles.  With the latter in place, ground the light socket to some non-movable portion of the body.

[Buick35]

I just added a woven ground strap from the frame to the body,still the same. I'll do like you said with the dome housing probably tomorrow.

[Grimy]

The woven ground strap connects the body electrically to the frame despite the anti-squeak (insulating) material between the two.  NOW, use a jumper to establish a ground between the dome light socket and the closest place on the body that will make the light work.  I trust you've already established that (1) you have 6V to the socket and (2) the bulb works.

[Buick35]

Yes,like I said the problem only happens on the passenger side front door.

[Grimy]

52 minutes ago, Buick35 said:

Yes,like I said the problem only happens on the passenger side front door.

It *could* be that the grease on the RH hinge is preventing the ground from being completed.  Perhaps see if the sheet metal on the B pillar would provide a suitable continuous ground--that might be the easiest path.

[Buick35]

Thanks.

[Buick35]

Grimy,I ran a wire from the dome light to a good ground on the dash and it works with the door open as it should. Mabe the door hinges are at fault,I don't know. Now what? I can't see how it would be too much grease but who kows?

Edited March 21, 2022 by Buick35
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[Grimy]

Don't worry about what the specific cause may be, just find a way to run a hidden wire to the good ground on your dash--or some other place closer if a closer place gives you the same result.

[Buick35]

22 minutes ago, Grimy said:

Don't worry about what the specific cause may be, just find a way to run a hidden wire to the good ground on your dash--or some other place closer if a closer place gives you the same result.

Thanks, I hate the idea of trying to feed a new wire in that right space though.

[Grimy]

Keep trying to find the easiest-to-access place to run a wire which will provide the ground.  Now you know that it's a ground issue, so the next step to to try grounds in different places that are much easier to feed a wire.