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1954 Series 62 Coupe Dome Light

Started by Nickl, March 27, 2020, 12:38:27 PM

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Nickl

Hey!
Have problem....
In my 54 2dr the done light did not work.
So I have a orange cable that is + and a black cable .
Both are going to the bulb.
I have power on the orange cable.
Another black cable is going to the switch at the dome light and I have also power on the cable.
When i open the door nothing happens.
So what could be wrong ?
I think at 2drs only the dome light will go when the doors are open wrigth but not the map light?
Thank you!
Nickl
1954 Cadillac Series 62 Coupe

J. Gomez

Quote from: Nickl on March 27, 2020, 12:38:27 PM
Hey!
Have problem....
In my 54 2dr the done light did not work.
So I have a orange cable that is + and a black cable .
Both are going to the bulb.
I have power on the orange cable.
Another black cable is going to the switch at the dome light and I have also power on the cable.
When i open the door nothing happens.
So what could be wrong ?
I think at 2drs only the dome light will go when the doors are open wrigth but not the map light?
Thank you!
Nickl

The “orange” is the power side the black wire at the switch would be the ground from either of the door switches. If you are reading voltage at the black is because you are getting the +12V from the dome filament bulb.

If you do not get the ground from either of the door switches there is a possibility the wire (black) going to the dome light is open somewhere in the hardness.

If you have the Service Manual Section 3 should have the wiring hardness layout last pages on that Section.



Quote from: Nickl on March 27, 2020, 12:38:27 PM

I think at 2drs only the dome light will go when the doors are open wrigth but not the map light?


That would be correct for all coupes
J. Gomez
CLC #23082

Nickl

Hey
Thank you!

I have the service Manual but the pictures did not fit with my car.
I have only one dome light in my car and the picture show 2... one of each side
The picture I added shows the dome light I have at my 2dr....
The cables are all okay...
Did someone have the wiring diagram for a 2dr series 62?
1954 Cadillac Series 62 Coupe

J. Gomez

Quote from: Nickl on March 28, 2020, 08:44:39 AM
Hey
Thank you!

I have the service Manual but the pictures did not fit with my car.
I have only one dome light in my car and the picture show 2... one of each side
The picture I added shows the dome light I have at my 2dr....
The cables are all okay...
Did someone have the wiring diagram for a 2dr series 62?

Someone can correct me if I’m wrong here.  ;)

The 6237 regular coupe has one dome light at the center while the 6237D Coupe Deville has them on both R&L side.

Unfortunately the generic wiring diagram does not show the layout for ALL specific models here is one and you can search on-line for others as well.

From the picture your posted, one of the tabs on the switch is connected to the body of the dome light metal cover (bottom tab on the switch) so the cover is grounded when it is mounted to the roof.

The other tab were the black wire connects the wire would be splice inside the hardness somewhere to the main black wire going to the bulb socket.

The main black wire would then extend and splice over to both R&L door switches.

So when you flip the switch at the dome it will place a ground from the metal cover over to the light and when either door is open the door switches will place a ground on the main black wire.

HTH

Good luck..!
J. Gomez
CLC #23082

Nickl

Thank you for the long answer and the wiring diagram you posted.
From witch book is the wiring diagram out? I only have the normal shop manual and the masters parts book.
They thing I don't understand is why I have +12 V on the black cable that goes to the switch or is this normal?
I'm located here in Germany so it's not so easy because here I can not ask someone for help
1954 Cadillac Series 62 Coupe

J. Gomez

Quote from: Nickl on March 28, 2020, 10:28:22 AM
Thank you for the long answer and the wiring diagram you posted.
From witch book is the wiring diagram out? I only have the normal shop manual and the masters parts book.
They thing I don't understand is why I have +12 V on the black cable that goes to the switch or is this normal?
I'm located here in Germany so it's not so easy because here I can not ask someone for help

I fully understand even here in the USA we Cadillac folks do not have local resources available close by that is why we have these resources.  ;)

The diagram I scanned it from the National Data Service book covering 1953-56 cars, I had to compress the file to fit the forum limitation since I tend to scan these to a high DPI resolution.

I’m not sure why you have +12V on the black wire since this would be the ground source from the door switch unless someone cross something in the main hardness or there is a short somewhere in there.   ???

Here is a diagram from the 1956 Service Manual showing the dome light for several models which I just finished correcting it since it had an error, hope this will help.

You will see the door switches from both R&L front doors going to the dome light and the red (label 18R) is the 12+v.

Good luck..!
J. Gomez
CLC #23082

Nickl

Thank you!
In the wiring diagram you posted for my 54 I can't find the dome light....
Have checked it several times or I'm blind  :-[
1954 Cadillac Series 62 Coupe

J. Gomez

Quote from: Nickl on March 28, 2020, 11:05:36 AM
Thank you!
In the wiring diagram you posted for my 54 I can't find the dome light....
Have checked it several times or I'm blind  :-[

It will not be in that one as I stated above that one is the generic wiring diagram so it will only show the general wiring to cover ALL models in general.    :(
J. Gomez
CLC #23082

Cadman-iac

The reason you have 12 volts at the black wire is because it passes through the bulb and will continue to the switch in the dome lamp and to both of the door switches.  It's only when the switch,  whichever one happens to ground out when activated, will the circuit be completed and the light will come on.
You can check the circuit for continuity right at the door switch, or dome lamp switch, by looking for voltage. You should have 12 volts right up to the switch. If you don't,  either the bulb is bad, or the wire is broken or disconnected.
HTH,

Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Nickl

Quote from: Cadman-iac on March 28, 2020, 12:25:07 PM
The reason you have 12 volts at the black wire is because it passes through the bulb and will continue to the switch in the dome lamp and to both of the door switches.  It's only when the switch,  whichever one happens to ground out when activated, will the circuit be completed and the light will come on.
You can check the circuit for continuity right at the door switch, or dome lamp switch, by looking for voltage. You should have 12 volts right up to the switch. If you don't,  either the bulb is bad, or the wire is broken or disconnected.
HTH,

Rick

Hey!
Okay... at the moment I have 12 volt at the orange cable and 12 volt on the black cable of the switch. Have installed a new bulb but the light will not go on.... have checked both door switches and they are working
1954 Cadillac Series 62 Coupe

Cadman-iac

#10
 The first thing to try is to take a jumper wire and ground the bulb at the lamp itself. That should tell you if you have a good connection between the bulb and the socket. You'll have to use a small probe and insert it into the ground wire, (the black one), right at the socket.

Do you know that you have 12 volts at the socket for sure? And that it's passing through the bulb? I ask because the little ends inside the socket that actually connect it with the bulb will deform over time, especially if they've gotten hot. They are made of lead, just like the ones on the bulb itself.  So if they don't connect because of this, the circuit will not be completed.
So if the connectors are in good shape and the bulb is good, and it will light up when you ground it at the socket,  then the next thing to check is the wire going to the door switches, and the dome switch.  I would check the dome switch first. Check for voltage at the switch, with it in the off position. There should be 12 volts there. If not, you have either a bad wire or a bad connection. Look for corrosion on any of the connections, and clean them up with a small wire brush if you can, or something that will scratch the surface to make a good connection. If you still don't have any voltage, check the wire for continuity between the socket and the switch.
If the wire is good,  and the connections are good, and you have 12 volts at the switch, the bulb should come on when you turn on the switch.
If it doesn't,  then it's the switch. It may just have dirty contacts, or it could be damaged. To verify it's the switch,  take the jumper wire and ground the wire on the switch. The bulb should work if everything else has checked out.
I don't know how your switch is put together,  but if it's like the one in my car, it's possible to open it up and check it out. Just be careful not to bend the little tabs too far or they could break off.
Check all these things out and if this doesn't find the problem, we'll go from there.
Good luck with your repairs, I hope it's just something simple.
HTH,
Rick

CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

J. Gomez

#11
Quote from: Nickl on March 28, 2020, 12:39:23 PM
Hey!
Okay... at the moment I have 12 volt at the orange cable and 12 volt on the black cable of the switch. Have installed a new bulb but the light will not go on.... have checked both door switches and they are working

You will need to do more testing to troubleshoot your issue, not sure what do you mean by “have checked both door switches and they are working”? ???

Do you have good continuity on both switches when they are close between the metal case and the main contact (door open)? ??? The metal case would be grounded to the chassis when they are in place.

In addition to Rick's comments above.  ;)

Remove the bulb from the socket, if you have a test probe light connect it to a good +12V source and check the black wire at the socket with the doors closed and the dome light switch off if you have it installed and the dome switch on the off position.

If you only have a voltmeter same, place the red to a good +12V source and the black lead to the socket.

The probe light should be off and/or the voltmeter should read no voltage.

Open one door and retest.

You should see the test light on or the voltmeter reading voltage. Close that door and repeat the same for the second door.

If you do not see the test probe light on or a reading on the voltmeter you have an open somewhere.  :(

Close all doors.

Reversed the test leads from the probe light or voltmeter, clip the black lead to a good ground source (anywhere is the chassis) and touch the “black wire at the dome light socket.

If you see the probe light on or a reading at the voltmeter this tells you there is a +12V source on the black wire from somewhere in the main hardness. No good..!  :(

“IF” you do not see the probe light on or read voltage from the above test, install the dome bulb back on the socket and clip a ground to the dome light black wire, the light should be on.

You need to take multiple steps to troubleshooting electrical issues to isolate the problem.  ;)
J. Gomez
CLC #23082

Nickl

Thank you for helping me with this issue....
Have tested the door switches
.. have Removed the from the car and with a test light I connected them to a battery so I can se if the light turned off when I press the door switch and both have passed the test... when I press the door switch my test light goes off
1954 Cadillac Series 62 Coupe

Cadman-iac

#13
Quote from: Nickl on March 28, 2020, 02:14:10 PM
Thank you for helping me with this issue....
Have tested the door switches
.. have Removed the from the car and with a test light I connected them to a battery so I can se if the light turned off when I press the door switch and both have passed the test... when I press the door switch my test light goes off
That's good, but you still need to know if there is a connection between the switch and the body, and you can only do that with them installed.
Since you have them out though,  take the wire and ground it at the door jamb. If everything else is working as it should,  the bulb should come on.
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

J. Gomez

Quote from: Cadman-iac on March 28, 2020, 02:18:17 PM
That's good, but you still need to know if there is a connection between the switch and the body, and you can only do that with them installed.
Since you have them out though,  take the wire and ground it at the door jamb. If everything else is working as it should,  the bulb should come on.

Ditto..!  ;)
J. Gomez
CLC #23082

The Tassie Devil(le)

#15
If you have 12 Volts on both the coloured wire, and the Black one (yes, I know black is a colour) then the light will not illuminate.   I found that out when I was wiring a car and couldn't figure out why I couldn't use a LED globe for the Ignition globe on the dash.

Bruce. >:D

PS.   In measuring the voltage on both wires, you have to remove the globe, to isolate the black grounding wire, and if there IS voltage on the Black wire, then it is not a grounding wire, as usually the case of the light holder is the ground.   What does the Black wire attach to?   The body, or what?
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Nickl

So here I have a little update.... the light is burning but only when I turn on the switch at the dome lightmanually... not when I open one of the doors.... so thing there must be something with the door switches or with the cables...
1954 Cadillac Series 62 Coupe

Nickl

So today checked all... the problem must be the connection between the door switches and the light....
The cables from the door switches are going under the dashboard. Do anybody can tell me where are the connected under the dash?
1954 Cadillac Series 62 Coupe

Nickl

Have to correct my last post... is it possible that the cables are going to the trunk at Coupes?
1954 Cadillac Series 62 Coupe

Cadman-iac

#19
Are you referring to the black ground wires when you mention cables?
There is a wire going to the trunk light,  but it will be an orange one to supply the power to it. The ground circuit for the trunk light is through the light mounting itself. There is no ground wire on the trunk light.

As for your dome light only working with the switch on the light itself, this tells me that the black wires have an issue. Either they are corroded or damaged, and you will need to do a continuity test on each of them to find out what the problem is.
I'm not sure exactly where the wires intersect under the dash or elsewhere, but I can check my old harness for that. I made a complete new one for my coupe by taking the old one apart and copying each wire exactly one at a time,and then assembled it into a new harness.
Now just so you know,  there are several separate individual harnesses that make up the complete system for your car. Unfortunately, the dome light harness is not one of them. It's part of the rear body harness,  but what I did with mine was to cut it off right where it comes out of the roof panel below the rear package shelf and I put in a dual wire connector. The reason I did this was because of how difficult it was to get it out of the car in one piece.
If you try this,  I would suggest that you use a good strong string tied to the end of the wire before you pull it out of the roof panel. This way you can use it to pull the new wire back into place. Otherwise it will be extremely difficult to get the wire to go back through the channel in the roof where it was originally.
The same thing for the wires in the trunk lid. Use a string so that you can get the wires back through the lid panels.

Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"