Courtesy Light

[mdelapp]

I'm trying to install the underdash courtesy light in my 53 Commander hardtop and connect to door switches and an under dash switch.
In looking at the wiring diagram and it does not appear that the light shows it being grounded but just two hot wires to it. One to the switch and the other to a power source. The switch shows 3 hot wires and no ground. The only ground indications are the door switches. Is this correct and if so does the light bracket and switch need to be insulatedd from the frame?
I'm trying to replicate this on a bench before I stand on my head unde the dash and so far getting confuesed. I'm using a 12V charger for power source (the 53 has been converted to 12V)
Thanks
Mike D

Mike DeLapp
Barrington, IL
53 Commander Hardtop

[N8N]

I believe that the switch in the courtesy light is a grounding switch and acts just like the pin switches in the door jambs. The hot wire goes straight to the bulb. There should be a little bullet adapter thing plugged into the switch, one male bullet on one end and two female bullets on the other. I didn't have this on my car so I just made one with a little piece of wire and appropriate crimp on connectors. The other leg from the bulb goes to this bullet adapter and so does the wire from the door switches. The way this works, the switch only manually turns on the light when the doors are closed OR allows the light to work automatically with the doors. Unlike modern cars there is no position that disables the light completely.

BTW the switch is the same as the map light switch on a C-cab truck.

good luck,

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[studegary]

i used to replace the switch with a three position switch so that you could manually turn the light(s) on, they would go on when the door was opened or they wouldn't go on, no matter what.

Gary L.
Wappinger, NY

1959 DeLuxe pickup (restomod)

[N8N]

that'll only work on a car without an overhead dome light as well. otherwise all you would be disabling would be the courtesy light under the dash, the wiring still goes directly from the driver's door switch to the dome light. I think '55 was the first year for the dome light in a C-K? is that correct? so that would actually work well for a 53-54.

Not sure why they had both lights in '55, but they did.

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[mdelapp]

I think my switch is missing something as it only has one female recepticle. The diagram has two hot wires going to the bulb. I like the way it is supposed to work but may just find a substitute switch.
I assume that any new switch would have a ground plug and just screw to the underside of the dash.
thanks guys
Mike D

Mike DeLapp
Barrington, IL
53 Commander Hardtop

[N8N]

nope, your switch is not missing a thing. what is missing, if it's not dangling on the end of the wire coming from the door switch, is the little metal bullet adapter thing. If you don't have it just take two short pieces of wire, stick both of them into a single male bullet and crimp, crimp a female bullet to each of the other ends, et voila. one goes to the ground side of the light, the other goes to the door switch, and the male bullet goes into the switch. The switch grounds the connector through its case (and from there to the dash) when you flip it. The thing you may be missing here is that the bulb used in the light is the same as a dome light bulb, the base of the bulb is not connected to either end of the filament, so that it may be ground switched. there are two "dots" on the bottom of the bulb, each one is connected to one end of the filament.

If you wanted to do what Gary is suggesting you would get a SPDT switch with a center-off position that would fit in place of the stock switch, connect the common to the ground side of the bulb, one of the other terminals to the door switch wire, and the other terminal to ground.

hope this helps...

nate

(would almost be easier to just do a quick drawing on a cocktail napkin and scan it)

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[Blue 15G]

My '54 K has both a dome light and an under-dash courtesy light. Don't know if the 53s had both or not.

[Jeff_H]

Its been awhile since I did this on my '53 but if I recall, Nate is correct and the switch is internally grounded so its only got 1 terminal on it. Mine was shot and all I could find that visually looked the same from the user point of view was a ungrounded toggle switch (SPST with 2 posts). I soldered a wire with a ring terminal on the appropriate post and screwed it to the dash with the rest of the courtesy lamp bracket. The bulb gets a hot from I think the same circuit breaker the headlights use (could be wrong since I don't have the diagram handy). The other terminal from the bulb has a Y in it with one wire to the underdash switch and the other goes off to the door switches. All 3 switches are in parallel in a logic OR so any one of them turning on grounds one side of the bulb. I also have 12v in my car and I remember having to special order that bulb from napa. The 2 prongs on it are not connected to the shell of the base so some other more common ones won't work (they'll be one all the time).

'53 hardtops only have the underdash lamp, no overhead. I think the sedans do have a overhead and no underdash?

Jeff in ND

'53 Champion Hardtop

[mdelapp]

Nate
If you have time, put it on a cocktail napkin and I will owe you the cocktail.
My email is: jmdelapp@comcast.net

Doe the fact that the metal bulb holder being attached to metal make a difference in the grounding? I got a bulb from an auto supply store and it has two filaments. Depending on which wire to the bulb holder I energize, I get either dim filament or bright filament. Obviously this must be a brake light/parking light bulb so will head off to radio shack for a new bulb.

Thanks for your patience and time

Mike DeLapp

Mike DeLapp
Barrington, IL
53 Commander Hardtop

[mdelapp]

the single filament bulbs I find only have a single point of contact on the bottom and will not hit the double contact in the lamp holder. Are there single filament bulbs with double contacts? If I use the double filament can I use the smaller filament for the door switch and the larger filament (brightest) for the manual switch under the dash?
I am guessing that the wire from the switch to the bulb go to the line of the lamp holder for bright and the other lines from the switch go to the doors. The remaining line from the bulb holder goes to a power source. Do I have this right?

Mike DeLapp
Barrington, IL
53 Commander Hardtop

[N8N]

mdelapp, I'm at work right now so can't access the info. for you, but on my web site (see .sig) is a table of various bulbs used in Studebakers, both 6 and 12V. what you want is a single filament, dual-contact-base bulb, I think I have it listed under "dome light."

yes, "big brother" filters me from viewing my own web site.

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[Jeff_H]

I went out to the garage and checked. What you want for a 12V bulb for the underdash is a #94 bulb. The one I got from napa is marked T94 on it. The base is isolated and its got 2 buttons on the bottom for the filament. It fits in my '53 and works fine.

There was a posting on the "other" stude forum some years ago with huge listing of 6v to 12v bulb equivelents that I saved. Could be Nate posted it, not sure. It was invaluable since I got all the dash bulbs, etc from it too.

Jeff in ND

'53 Champion Hardtop

[N8N]

Here's the list I was thinking of:

http://home.comcast.net/~njnagel/files/12vbulb.htm

Jeff is correct, a 94 or 1004 is what you want for 12V; 88 for 6V.

good luck,

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[N8N]

To the OP: do you have this figured out yet, or would a sketch still help? I haven't been near a scanner all week but can try to whip something out for you this weekend if it will help.

good luck,

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel