Small switch on rear driver side, what does it control?

SMOKESHED

MEMBER
1967 CADILLAC DEVILLE
7.0L
V8
2WD
AUTOMATIC
120,000 MILES

There is a small switch on the rear driver side in my car listed above. I am trying to find out what it controls. Also, my rear interior lights will not turn off. Can these two be linked? I put a bulb in and toggled the switch, but the light would not turn off. Last thing I checked the power on the driver side rear light with a light meter and I have power, but the passenger side does not.

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1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,913 POSTS

In a 1967 Cadillac DeVille, the specific functions of switches and electrical components can vary depending on the options and modifications the car may have undergone over the years. However, I can offer some general guidance based on common setups of that era.

Small Switch on Rear Driver Side:
The small switch you've mentioned could have a few possible functions:

Trunk Light Switch: In many older cars, a switch near the rear driver's side might be associated with the trunk. It could control the trunk light, which turns on when the trunk is opened and off when it's closed.

Fuel Filler Door Release: Some cars have switches for releasing the fuel filler door from the interior. If your Cadillac has a locking fuel door, this switch could be related to that.

Rear Interior Lights Not Turning Off:
The issue with the rear interior lights not turning off could indeed be related to the switch you've described. If the switch controls the trunk light and it's stuck or malfunctioning, it could be causing the lights to remain on. Alternatively, there could be a problem with the door jamb switches that control the interior lights when the doors are opened or closed.

Here are steps you can take to diagnose and potentially resolve the issue:

Check Trunk Light Switch: If the switch on the rear driver's side is indeed related to the trunk light, check if the switch is stuck or damaged. If it's malfunctioning, it could cause the trunk light to stay on. You might need to replace the switch or adjust it.
Inspect Door Jamb Switches: The interior lights in older cars are often controlled by switches located in the door jambs. When a door is opened, the switch is depressed, turning the lights on. When the door is closed, the switch is released, turning the lights off. Check these switches to see if they're functioning correctly. They might be dirty, corroded, or misaligned, causing the lights to stay on.

Check Wiring: Examine the wiring associated with the trunk light switch and the door jamb switches. Look for any frayed wires, loose connections, or damaged insulation that could be causing electrical issues.

Bulb Issues: Make sure the new bulb you've installed is the correct type and properly seated in the socket. An incorrect bulb or a loose connection could also contribute to the problem.

Regarding the power discrepancy between the driver's side and passenger side rear lights, it could be due to wiring issues, a blown fuse, or a malfunctioning switch.