1941 Buick interior lights & button switches

[Matt Harwood]

I think these lights work pretty much the same on all cars, so I figured I'd as here rather than down in the Buick section. I'm trying to get all the interior lights working on the '41 Limited, and so far I've gotten all of them working correctly except these little lights on the corners of the front seat. They're supposed to come on when the doors are opened but they've never worked. One side is missing a lens, which I just acquired, while the other side is OK--the lens is cracked but nobody will notice down there. There is no wiring attached to either of the housings. It looks like I'm going to have to completely re-wire the lights and their switches, since there's nothing there now. Unfortunately, these don't show up on any wiring diagrams in the manuals, either, which is not unexpected. I believe similar lights were used on the Super and Roadmaster front seats, but I'm not positive.

 

My first question is how the door jamb button switches work. I have always believed they work by grounding the circuit, correct? When the door is open, the button is extended, and that provides a ground path for the circuit and the bulbs light up. That's why there's only one terminal on the button switch and only one wire going to it. From a safety standpoint, it makes sense to not run power to the door jambs. In operation, the housing itself screwed to the door jamb provides the ground, correct?

 

However, it also appears that the bulb housing bolts to the metal seat frame, which is bolted to the floor, which presumably is a ground path as well. I'm confused about how this works because the socket has two wires, but it has two terminals for a two-element bulb (that's my second question--why a two-element bulb?!?). There is no ground wire and no terminal on the housing for a ground wire. 

 

Any thoughts on how this should be wired? I can get power to it easily enough, but how is the socket grounded and how does it work with the button switches in the door jambs? I'm making this up from scratch, so I don't have any old wiring to go by.

 

Here's the socket, which you can see has two wires and two contacts inside. The outside of the housing is obviously the ground.

 

 

 

Here's the socket in the seat on the car:

 

 

 

How do I wire this so it comes on when the doors are opened, and why do you suppose it has a two-element bulb in there? I do not believe it should come on with the dome light, which is on a separate manual switch (which makes sense--the owner of a limousine would not want the front dome light shining in his face every time the chauffeur gets in or out of the car, but the lower seat lights would be useful so he can see what he's doing). 

 

Any thoughts for how to make this work? I'm wracking my brain trying to figure out how the ground path works. Thanks!

[DonMicheletti]

All the cars I have worked on, the door switch does provide the ground when the doors open

Since the light socket has 2 contacts, I'd think that one of those leads is a hot feed and the othjer the switched ground. I doubt that the body of the socket is a ground.

I doubt that there would be a 2 filament bulb there lights.

Is there any trace of  2 wires going to the seat asembly?

 

Also, I doubt that the seat itself provides a ground since it moves and might not provide an adequate ground.

[Matt Harwood]

3 hours ago, DonMicheletti said:

All the cars I have worked on, the door switch does provide the ground when the doors open

Since the light socket has 2 contacts, I'd think that one of those leads is a hot feed and the othjer the switched ground. I doubt that the body of the socket is a ground.

I doubt that there would be a 2 filament bulb there lights.

Is there any trace of  2 wires going to the seat asembly?

 

Also, I doubt that the seat itself provides a ground since it moves and might not provide an adequate ground.

 

That's the weird thing--look at the socket again. Two wires, two terminals, looks like it's designed for a two filament bulb, but there's no ground. The housing has to be the ground path, right? That's what's so confusing.

 

There are no wires in under the seat--I'm guessing that they never installed them when the interior was restored, so I don't even have a reference for how it should be. I pulled the one socket out to get a better look at it, and my only conclusion is that it grounds through the mounting screws into the seat frame. Should I run a ground wire to one of the mounting screws and somehow isolate the socket when it's mounted in the seat? I could probably put a rubber gasket on both sides to keep it from touching the metal seat frame, maybe use plastic screws. Would that work?

[Joseph P. Indusi]

Don is correct.   The bulb that goes here is a single filament with one end of the filament going to each of the contacts on the base.   One contact is wired to the door switch.   The other contact is wired to a +6 volt source.   The body of the bulb and the socket may or may not connect to ground but they are not part of the circuit. 

Nearly all sockets that are used with a dual filament bulb will have one of the socket side channels longer than the other so that the bulb can only be inserted into the socket one way.   This is most common on the stop and taillight combination bulb systems.

Joe, BCA 33493

[Frank DuVal]

Ding Ding Ding, Joe is correct. This is a single filament Double Contact bulb, like a 1004 lamp. NOTE I say LIKE as the 1004 is a 12 volt bulb! The shell of the bulb has NO internal connection to the lamp, it just holds the lamp in the socket.

 

Make one wire of the socket go to + six volts (Buick’s are negative ground) and the other wire to the door switch.

[Frank DuVal]

A # 64 miniature lamp looks right for this application.

 

http://www.bulbtown.com/64_Miniature_Bulb_Ba15d_Base_p/b64.htm

[Matt Harwood]

Great, thanks guys! It sure didn't look right to me, but a special dual terminal bulb would certainly explain it. Thanks for the link, Frank!

 

I'll probably tackle the project this weekend so we'll see how it goes. Nice work, gentlemen!

[Matt Harwood]

Bulbs ordered! Thanks!

[DonMicheletti]

When I restored my '38 Roadmaster many years ago, a replacement front wiring harness was not available. I ended up using a Century harness. Just barely fit.

It may be that when your car was restored, there was no harness available for a Limited and an alternative was used that did not have the seat wiring included

[Matt Harwood]

22 hours ago, DonMicheletti said:

When I restored my '38 Roadmaster many years ago, a replacement front wiring harness was not available. I ended up using a Century harness. Just barely fit.

It may be that when your car was restored, there was no harness available for a Limited and an alternative was used that did not have the seat wiring included

 

Thanks, Don. I didn't mean to doubt you, I just was having trouble wrapping my head around the two-terminal socket. I had no idea there were bulbs with two terminals and one filament. Since this part of the car isn't covered in the manual, the bulbs aren't listed there, either. Thanks for the great advice!

[DonMicheletti]

No offense taken

[edinmass]

Matt...I came across that two months ago..........I had never seen it.

[ILIKECARS53]

Hi Matt ,  I am not sure if the 1941 Buick manual has the courtesy lamps diagram, but the 1942 does have it for the different models.  I attached the diagram for 90 series models.   Good luk

[Matt Harwood]

5 minutes ago, ILIKECARS53 said:

Hi Matt ,  I am not sure if the 1941 Buick manual has the courtesy lamps diagram, but the 1942 does have it for the different models.  I attached the diagram for 90 series models.   Good luk

 

 

Fantastic! Thank you! That is extremely helpful.I should probably pick up a '42 manual since it seems to be a bit more comprehensive than the '41. Thanks for the tip!

[1939_Buick]

9 hours ago, Matt Harwood said:

 

Fantastic! Thank you! That is extremely helpful.I should probably pick up a '42 manual since it seems to be a bit more comprehensive than the '41. Thanks for the tip!

 

Download the 1942 Buick shop manual. All of it section by section. The pdf link does not work.

http://www.oldcarmanualproject.com/manuals/Buick/1942/Shop%20Manual/

It is very comprehensive and has information that can be used with all straight 8’s.

It has more information than was included in older “Shop Manuals” before 1942-41

 

Section 13 page 300 seems to be in the post above

 

Edit

Rockauto also sell on CD & maybe hard copy repro

Edited November 16, 2018 by 1939_Buick (see edit history)

[Frank DuVal]

Just note the two wires going to each lamp in that diagram are separate wires, going to the two different contacts at the base of these bulbs. 

 

The "Rear Courtesy Lamps" had me going for a minute, then I realized there were two lamps in each light assembly!

 

The #64 lamp is just a double contact version of the common #63 lamp used in many 6 volt license plate (and other places the grounded shell is no problem) applications. 

[Matt Harwood]

After some headaches, I now have working interior lights! Dome light works as it should, on a separate switch:

 

 

 

And the seat lights work when you open one of the front doors, just as they should:

 

 

 

Thanks for all the help, guys!

Edited November 19, 2018 by Matt Harwood (see edit history)

[Frank DuVal]

Yea!👍

 

Let there be light, inside.

[DonMicheletti]

Fantastic !

Did you have to run new wires for them, or did you find ones that had not been connected?

[Matt Harwood]

46 minutes ago, DonMicheletti said:

Fantastic !

Did you have to run new wires for them, or did you find ones that had not been connected?

 

All new wires. A considerably bigger job than expected, just because the last guy in there did it wrong, couldn't get the lights to shut off, so he just started clipping wires. Ugh. A simple job ended up taking all weekend, but everything works properly now. Here are details: