Trunk light

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CRUZE 418

CRUZE 418

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Okay electrical brainiacts, how did the factory isolate the bulb socket bracket for the trunk light? Just installed one in my car and the light stayed on with the switch plunger in. I know how to get around it, but want to know how the factory did it.
 
I am taking a guess here, don't know the year, make and model of car, but in my 70's manual it shows a dual contact bulb socket. One wire for power and the other for switch plunger (ground) to complete the circuit.

Screenshot (157).png
 
Yes, but the bulb socket bracket is always grounded, so the light stays on, the bracket bypasses the switch. Here's what I made to isolate the bracket.

20241229_160755.jpg
 
Our 67 cuda trunk light doesn't have isolator on the bracket. Dunno why yours stays on, sorry. Parts manual may have answers?
 
If it's grounding through the bracket, you've got a bad socket assembly.
It should ground through the switch, not the socket/bracket.
 
There are 2 wires going to the double pole bulb socket one wire is constant hot to the bulb. The other wire is the ground that goes to the switch. If you ground the black wire the light goes on. All the switch does is grounds that wire. If the light doesn't go off with the switch depressed the switch is shorted to itself.

So if you unplug the switch the light should go out If you touch the wire to ground it should light up. Do you have a double pole bulb installed. That is what goes in that socket.

Could the bulb socket be shorted . Because the light should not go on without the black wire grounded.
 
CRUZE 418 said:
Yes, but the bulb socket bracket is always grounded, so the light stays on, the bracket bypasses the switch. Here's what I made to isolate the bracket
Click to expand...
If you have the correct dual contact bulb the outer part of the bulb does not come in contact with either end of the filiment, so grounding the housing is irrelevant.

Just like the map light and the dome light.

They all have constant power but only are illuminated when the door switch or dimmer switch makes contact to ground.

I think either... You have the wrong bulb, the wrong socket, or something is shorting inside the socket.
 
Dana67Dart said:
If you have the correct dual contact bulb the outer part of the bulb does not come in contact with either end of the filiment, so grounding the housing is irrelevant.

Just like the map light and the dome light.

They all have constant power but only are illuminated when the door switch or dimmer switch makes contact to ground.

I think either... You have the wrong bulb, the wrong socket, or something is shorting inside the socket.
Click to expand...
I think either... You have the wrong bulb, the wrong socket, or something is shorting inside the socket.

^^THIS^^

WHAT ARE WE WORKING ON? Year, make, model
 
It's a '69 Road Runner. Must be something going to ground in the socket then. Switch did nothing. Remove the socket/bracket, light out. Touch the bracket back to ground, light on. It works as it's supposed to with my isolated. Will take a look at the pigtail in the socket. I have an 1176 bulb in it.
 
Okay, pulled the two wires ttorhrough the plastic disc, both wires are sound. Yes, I agree with all of you. But like Rooster says in Top Gun Maverick, ' It's not working! ' I am not good at trouble shooting, so I will just reinstall the isolator, I'm okay with that.
 
I just wired mine up like a dome light. I used an extra sail panel light and harness I had. Constant power one side and ground through the switch on the other. I wired it so when the trunk is open, the interior lights come on too. I WAS gonna go back and isolate the trunk light, but Kitty made the astute observation that most times we're in the trunk, we're in the inside of the car too. So it stays like that. The boss woman has spoken.
 
Okay guys, how about this. Jawbone and I were just talking, he's a retired electrician. The electrical gods are saying that it is grounding somewhere, we argued back and forth. All of a sudden it hit me, could the spring be touching a wire and the socket casing. Jawbone says, I think that you just figured it out. Not going to take it apart and try to correct it. It works with the isolator that I made.
Thank you guys, you have forgotten more than I will ever know about electricity!
 
Just a thought...

If he light stays on could it gets hot enough to damage the cars paint.

To me that would be a good reason to make it right.

Not to mention an accidental touch with a metal part to ground can make a spark when not intended
 
Dana, if you look at the insulator I made, it now works as intended. Nylon washer with a shoulder protrudes through the hole in the mounting bracket from one side, and another washer from the other side goes over the shoulder. Screw hole's through to mount to the bottom of the Dutchman panel skeleton. I think that it's safe, but will see if I can get the thing apart without destroying it.
Thank you!
 
I understand what you did but let's say you put a lawn chair in the trunk and it comes in contact with the body of the light housing and a metal part of the car body, the light comes on. Now let's say the bulb is in contact with the webbing and gets hot enough to start it on fire
 
Super-Cuda said:
If you are using a 1157 bulb, that's a dual contact bulb, usually for brake/turn signal.

You need a 1070 bulb, single contact.
Click to expand...
WRONG. He needs a SINGLE FILAMENT, DUAL contact lamp. The service manual says 1004 same as dome. He says he has a 1176 and that should work as well. Charts show 1004 is 12 watts, 1176 is 17, and larger globe
 
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Will see if I can get a # 1004 bulb. I thought that the # 1176 bulbs glass was larger. The # 1176 was the only single filament bulb that had the lower locking pins. I can order a # 1004, but will.see if one of the stores can get it. Will see if that socket will come apart and see what's going on with the spring.
Thanks again, will let you know.
 
67Dart273 said:
WRONG. He needs a SINGLE FILAMENT, DUAL contact lamp. The service manual says 1004 same as dome. He says he has a 1176 and that should work as well. Charts show 1004 is 12 watts, 1176 is 17, and larger globe
Click to expand...

My bad.

I should have checked my car first as I confused this with something else.

Here's a pic of the actual harness, the bulb and the connection harness for reference.

As 67Dart273 said, single filament duel contact, which is clearly evident in these pics of a NOS setup.

Under Hood / Trunk Lamp Pkg# 2580612 - A - B - C - E - Body - 1966-71 - NOS - SHIPS FREE TO LOWER 48 - Blue Star Performance
 
CRUZE 418 said:
Will see if I can get a # 1004 bulb. I thought that the # 1176 bulbs glass was larger. The # 1176 was the only single filament bulb that had the lower locking pins. I can order a # 1004, but will.see if one of the stores can get it. Will see if that socket will come apart and see what's going on with the spring.
Thanks again, will let you know.
Click to expand...
The bulb you have should be fine, but take your meter and the bulb and check for continuity from either of the contacts to the shell. It should be open/ infinity. You already know the bulb works, but one filament contact may be (fault) grounded to the shell
 
Super-Cuda said:
My bad.

I should have checked my car first as I confused this with something else.

Here's a pic of the actual harness, the bulb and the connection harness for reference.

As 67Dart273 said, single filament duel contact, which is clearly evident in these pics of a NOS setup.

Under Hood / Trunk Lamp Pkg# 2580612 - A - B - C - E - Body - 1966-71 - NOS - SHIPS FREE TO LOWER 48 - Blue Star Performance
Click to expand...
Believe me, keeping track of bulb no's is harder at my age. In my "yute" we used to have small brochures from people like GE/ Sylvania/ Tung Sol with listings of the bulbs the bases, voltage and wattage, etc.
 
67Dart273 said:
Believe me, keeping track of bulb no's is harder at my age. In my "yute" we used to have small brochures from people like GE/ Sylvania/ Tung Sol with listings of the bulbs the bases, voltage and wattage, etc.
Click to expand...

:thumbsup: :thumbsup:
 
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