GLOVE BOX LIGHT

[LAS VEGAS DAVE]

My clock has a bracket riveted to it that hods a bulb pointed towards the glove box. There is no switch inside the clock or on the glove box door that would activate the light. How does it turn on? The car is a 38 Special. 

[Dynaflash8]

It is a Mercury Switch.  It automatically comes on when you open the glovebox door and goes off when you shut it.  The trunk light is the same way.

[LAS VEGAS DAVE]

WHERE IS THE SWITCH LOCATED ON THE 38? DOES ANYNE HAVE A PICTURE OF IT?

[MCHinson]

I am assuming that the 1938 is the same as or similar to the one in my 1937. I don't think it is actually a mercury switch, maybe it would best be described as a gravity switch. It works like a mercury switch but is better. While I have not disassembled it since it works just fine, I think it is more of a small ball bearing that rolls into position by gravity to make the electrical connection when you open the glove box door.  If you slide the bulb socket out of the sleeve that it slides into, and remove the bulb, you will find that you can shake the socket assembly and hear what sounds like a small ball bearing rolling around. If you reinstall the bulb you can experiment with it (while keeping the socket grounded against the bracket) and turn the bulb on and off by moving it around at different angles. It is a very simple, inexpensive, yet elegant solution to the problem of switching the light off and on. The more I learn about Buicks of this era, the more impressed I am by their engineering. 

[LAS VEGAS DAVE]

Thanks Matthew, my socket looks a little longer than a normal one so I need to look investigate it more. Maybe the bearing is stuck.

[MCHinson]

If it is not working and the bulb is good, I would think that you could probably slide the socket out of the assembly, and shake the socket a bit and probably get the switch to start working again.

[LAS VEGAS DAVE]

The diaphragm on my fuel pump tore so today I was working on it. I will try your suggestion after the fuel pump is fixed and back in the car. I think I have to first see if I'm getting juice through the wire that leads to the socket and then go from there. 

[LAS VEGAS DAVE]

I fixed the fuel pump so I decided to look at the glove box light. Matthew is correct about the switch being the light bulb socket itself. I shook mine and could hear the bb's rattling around but I could not get juice to the bulb. I did have juice going to the socket but the bb's were not connecting the juice to the lightbulb terminal. I finally took the socket apart. It contained 4 bb's about one fourth the diameter of a regular bb like the ones you shoot in a bb gun. I cleaned the bb's in a electric terminal cleaning solution and then took a dremmel and miniature wire brush to all the surfaces the bb's touch to complete the circuit. It still didn't work perfectly. Sometimes it works sometimes it doesn't. I took it apart one more time and added two real bb's from my bb gun collection keeping the smaller ones also. It seems to be working better but still not perfect, it lights about 80% of the time. In any case its an amazing little device that I didn't even see as anything other than an ordinary socket until closer inspection.  Thanks again Matthew for the help.