1949 Jeepster Switch Under Gas Pedal

Hello everyone, I need some help. I have a 1949 Jeepster that I inherited from my grandfather and I am in the process replacing the wiring harness. I have a switch under the gas pedal that has wires going to a relay and I have no idea what this switch does. My grandfather upgraded the car to a 12 volt system. If anyone has any ideas please let me know. Also I am lost with how the overdrive works on this thing. Looks like it is a pull out button under the dash. Do you leave it pulled out all the time or what? This car means a lot to me and I don't want to do anything that will ruin it. Thanks for your help.

The pull-out button is the overdrive "on-off" control. With the button pushed "in", the overdrive is in operation.. "Out" disables the overdrive.

The button under the accelerator is the kickdown switch. It was a "kick it" switch to give acceleration when in overdrive. With the accelerator depressed, the overdrive downshifted to give better acceleration.

The overdrive used 6-volt solenoids, so the 12-volt conversion may or may not have included the overdrive controls.

I would suggest you get the shop manual for the 1949 Jeep vehicles. You will need it and the transmission/overdrive section (usually Section K) explains just what the overdrive is and how it works.