Interior lighting lights…

[BE_Fury]

The interior light on my 1971 Plymouth Fury III won't go out... I replaced the thermal time relay because the old one was very oxidized.

I then wanted to replace the bulbs. Previously there were none. Now the light sources shine continuously.
There are two contacts in the socket. One has 12V. For the other 0 V. How do you turn on the interior lighting?
Should the lights turn off at some point?

I found an empty port. What would belong in there?

 

[FURYGT]

Is the dash dimmer switch up all the way? As you turn up the dash lamps dimmer there is a “bump” and if you go past this bump that switch will turn on the interior lights. The dimmer switches are known to fail. Sometimes some electrical contact spray will help.

If that doesn’t fix the problem, pull out the door jamb switches and inspect or replace them. There’s always power to the interior lights. The dimmer switch and the door jamb switches create a ground to complete the circuit to turn the lights on.

 

[Big_John]

There are two contacts in the socket. One has 12V. For the other 0 V. How do you turn on the interior lighting?
Should the lights turn off at some point?

There is always power to the sockets.

The light is turned off and on by the door jamb switch providing ground.

If you check that socket, with the switch on, you should be able to get 12volts when you touch the probes from your voltmeter to both contacts (meaning one probe on each contact). The yellow wire is the switched wire (provides ground) and the pink wire is constant 12volts.

As @FURYGT mentioned, the dash dimmer could be turned all the way up past the detent and that turns on the interior light. If it's not that (I bet it is), the yellow wire is touching ground, like the insulation is cut and touching the metal, or one of the switches is bad.

Oh... and just a random thought.... Do you have the correct bulb? One with a single contact would probably stay lit if someone managed to cram it in there.

 

[BE_Fury]

The dashboard dimmer was turned past the detent and turned on the interior lights. I turned it back and now the passenger side light is off when I close the door. But the driver's light stays on.

I have to check the contacts. Thanks in advance. I didn't know the function of the dashboard dimmer.

 

[BE_Fury]

I have now checked the contacts. Everything is OK here. What could be the reason why the light on the driver's side doesn't go out?

 

[Big_John]

I have now checked the contacts. Everything is OK here. What could be the reason why the light on the driver's side doesn't go out?

That socket that you've shown in the pic looks like something someone has added. If so, trace the wiring if you can. Is there a switch that may have been added?

Also, check the yellow wire for breaks in the insulation or anything that could be making it short to ground.

And I'll ask again... Is the correct dual contact bulb being used?

 

[BE_Fury]

That socket that you've shown in the pic looks like something someone has added. If so, trace the wiring if you can. Is there a switch that may have been added?

Also, check the yellow wire for breaks in the insulation or anything that could be making it short to ground.

And I'll ask again... Is the correct dual contact bulb being used?

Yes, the dual contact bulb is used.

I couldn't find a switch or anything similar.
The cable insulation is a bit dry, but I couldn't see any breakage.