Folks, I installed a NOS 1947 1948 6-Volt clock. I'm running 12-Volts in the car. I used the fuel gauge transistor voltage reducer (the one with the little pigtail for ground) but nothing happened. Clock wasn't working. Do you guys know which voltage reducer I should use? Thanks in advance.
First test the clock on a 6V battery. Rotate the clock while connected to see if it ticks. Use synthetic clock oil to lubricate if it stops. You can get this oil in a long pen like tube with a very fine needle applicator. Place clock on bench at the same vertical position it is mounted in the car. The coil contacts can be tarnished from age. Clean with one drop of silver cleaner applied with paint brush. Remove cleaner drop with paper towel. If your fuel gauge works so should the clock. The clock should run for a few minutes on one charge of the spring.
First you need to determine which model clock you have. If there is only one wire I expect it is a wind-up clock. The wire is for the light.
If it is an electric clock, you will need to do some research to determine what size resistor you need so you get 6 volts to the clock motor. The resistor must have the same resistance as the clock motor so it takes half of the power and voltage.
A fuel gauge resistor might not be the correct choice. It might be the wrong resistance plus it might not be able to handle the amperage that the clock motor requires. The fuel gauge circuit does not draw much current.