I am rebuilding and refreshing my dash light and had a few questions.
The first question is what side of the light bulb socket plate faces the light bulb? (This is the part the long pin goes through to turn the light on and off) There are two different sides and I don't think mine was put together correctly at some point during its life. One side has smooth contacts and the other side has a dimpled contact surface. Do the Smooth contacts go against the bottom of the light bulb or do they go against the spring loaded pins in the socket base.
The part in question is in the middle of the last two pictures.
Last question is: What is the best spot people have found for the ground wire. I was thinking about putting the ground wire on one of the two dash light attachment screws with a ring terminal. Any thoughts on this?
I've only seen one partially apart. I believe the rounded end of the contacts (your second pic) go against the bulb contacts. Was the fixture body grounded originally? with a 2 contact single filament bulb the ground is the second wire going to the bulb. The silver bulb base isn't usually ground on a bulb of this type. Take, for instance, a T head light bulb. 1 filament & 1 contact. The metal bulb base is the ground. On the bulb shown the second contact on the bulb is the ground. If so the metal fixture doesn't need a ground wire at all as the second contact should provide one.
I can't help you very much, but can tell you this. Your dash light is not the one that Ford supplied. The Ford one doesn't use a ground wire, and the mounting holes may be spaced differently, but still uses two screws. I hope I didn't upset you. The Ford model is pictured in the late parts books.
Larry, This Dash light is for my 1922 Touring and was an accessory that was bought at some point later for the car, so no big deal if its not a Ford. I didn't know Ford made and installed dash lights? What does the Ford Dash Light look like?
Charlie, As far as the contact sides, I thought that the smooth contacts should go toward the light bulb myself but I can see it being best either way because it has to rotate against the spring loaded pins in the bottom too, plus the light bulb contacts.
This bulb is a two contact bulb so it needs the ground wire to work but I was going to just hook it to one of the dash light mounting screws that mounts the light to the dash creating the ground to the frame. Will that not work? Where is the best place to put the ground wire?
Sure that will work. Put in a short ground wire with a terminal on it and put it on one of the screws from behind the dash.
Thanks Charlie, I just needed to get some reassurance because you never know, there might be a better spot that someone has found. I thought that sounded the easiest.
Anyone with a solution to the correct Contact side to use? I think if someone could pull there dash bulb and flash a light in on the bulb contacts they might see one side or the other. I guess provided it looks close or operates like this one.
Is the contact fiber plate fitted to the lever to switch on the lamp? If so, then the lamp is stationary, and the contact plate swivels to make contact with the lamp. If the lever mounts to the bakelite plug, then place the contact to allow the best electrical connection. The rounded discs on the contact would be the easy ones to slide over the lamp contacts.
As Larry posted, most of the T dash lamps, factory or aftermarket use a single contact 6v bulb, and the ground is made by the dashlamp base to the instrument panel, with its ground path to the chassis.
In the above post the lamp with the aluminum home made mounting plate is actually a real Ford dash lamp, missing the lamp shield.
This catalog page is from 1920 Sears Roebuck auto parts brochure, showing styles of aftermarket dash lamps.
Here is a better picture of what my Dash Light parts do. The contact piece in the center rotates and the light bulb and contact base with two spring loaded pins are fixed and do not rotate. The Pin in the picture goes through the middle of the rotating contact plate and that is what turns the plate and both sets of contacts.
This is the way I think that it works but I could be wrong. I can see where the rotating contacts would work either way but the spring loaded pins might work better and operate smoother with the smooth contacts of the rotating piece facing down touching the pins.
that's how I'd do it. With a spot of lube on the bulb contacts to ease operation.
Now that I look at the bulb closer it has smaller smooth rounded contact tabs.
So this being the case I think the best way to put this together is with the larger smooth contacts of the rotating piece toward the back touching the spring loaded pins. The dimpled side seems to fit the smooth light bulb contacts very well so that side should go to the front. That way everything has a smooth contact to ride on.