Help solve a minor electrical mystery

The cigarette lighter in my 57 Thunderbird has never worked, and this weekend I finally decided to do something about it. I admit I'm not great with electrical work, but what I found doesn't make any sense to me.

Here's the lighter I pulled out of the car:

I have no idea what that thing on the end is, but both wires had loop terminals fastened to it. I have no idea why that wasn't causing a short, but it wasn't. This was on a fused circuit, and the fuse was intact. I replaced the lighter and it works, so the 12v + wire definitely has power running to it.

All looks pretty normal except for that thing on the end, and the fact that there's no ground tab on the side of the body. Sure, that could have snapped off, but I don't see a spot with an obvious solder mark/spot weld where it would have been. 

This doesn't seem to be a factory part. I looked up reproduction lighters for the T-Bird, and they look like the normal, universal style with the ground tab on the side of the body.

Also, the clock may somehow be related to this. It hasn't worked since I removed the old lighter, and while it's possible it stopped working before then, it seems unlikely. It may be related to this problem, or I may have just blown a fuse or yanked a wire loose by accident. Haven't had time to check.

So, my questions:

WTF is that thing on the end of the lighter?

Why wasn't the power and ground wires touching and connected to the same terminal causing a short?

I think you are missing some parts. 

Are you sure that second wire was a ground and not power going to the clock? With a metal dash there may not have actually been a ground wire.

In reply to dean1484 :

Such as?

My guess is one wire was the positive to the lighter, and the other was a positive continuing on, probably to the clock. The "stud" is the + post and - comes from the outside touching the body metal. There is no - wire on old cars. 

The stud is the hot terminal, the round doodad between the stud and body is a doodad of some sort...

The ground is likely through the body of the lighter to the sturdy steel dashboard.  The second wire likely is the power supply for the no functioning clock.

If you look down the hole where the heating element goes, there should be some sort of contact that the middle of the lighter element touches when it's plugged in.  You need to figure out where the power stops.  Voltage at the stud...voltage through the doodad...voltage to the contact...voltage into the element...voltage through the element...grounded body. By far, the most common failure is the element itself.

Steve_Jones said:

My guess is one wire was the positive to the lighter, and the other was a positive continuing on, probably to the clock. The "stud" is the + post and - comes from the outside touching the body metal. There is no - wire on old cars. 

Okay, winner winner. I disconnected what I thought was the ground wire, and the lighter still worked. So I connected that wire to the lighter power wire, and the clock now works.

Thanks hive and Steve in particular.

You need to quit smoking. Problem solved!

I don't smoke, but I like to be able to run a battery charger for a phone, tire inflator, etc.

Also, I should thank Oldopelguy for making the same guess Steve Jones did. Didn't mean to leave you out.

Edit: I'd still like to know what that thing on the end of the old lighter is, if anyone knows.

Will said:

Edit: I'd still like to know what that thing on the end of the old lighter is, if anyone knows.

It's a henway.

In reply to Will :

It's OK, my name is Stephen too, so I just assumed you knew.

The "thing on the end"...

You mean the threaded stud on the back of the lighter base?  That's where you are supposed to be mounting the positive electrical leads to. 
 

Did you mount them elsewhere?

The body of the lighter is negative. It is grounded to the battery by being mounted in the steel dash of the car (which is also negative). If you mounted the positive leads to the body of the lighter, you reversed it (which should have blown a fuse). 
 

There was no ground wire on old lighters. 

My guess is that when they went from 6V to 12V in '56 or so they just added a resistor element to the existing lighter to drop the voltage. Probably just a resistor. If you measure the resistance of the heating element in the plug, it is probably similar to the resistance of that element. That would confirm my guess. Jcamper

In reply to SVreX (Forum Supporter) :

No, I mean the thing between the stud and the body of the lighter. I've not seen that on any other lighter.

The reproduction 56-57 lighters don't look like the one in my pictures (missing the thing in question). But maybe JCamper is right and they added that thing to their existing supply of 6V lighters.

circuit breaker ?     Heat sensor ?

So then you would be getting 6 V at the lighter.    Won't work very well for 12v devises.

It's either a resistor or a fuse/circuit breaker...