Classic/Antique Car Repair: overdrive light up lamp on dash, high speed pursuit, overdrive

Question
i bought a 1964 chevy pick up.it has a sticker on the dash that says.."use overdrie when in high speed pursuit" this sticker istre and original to truck.on the dash there is a area about 1/4" in circumference of orangish plastic that has OVERDRIVE etched on it.it is supposed to light up when i guess overdrive is in use.my question is that know one yet has answered is...where is overdrive switch etc ad how do i turn it on?

Answer
Trace the wires from the transmission to find the switch. No wires, no overdrive.


I have never heard of this in a PU, Don't know if an inventive teenage in the 60's swapped parts, or it is just something I've never heard of, but ..... wires don't lie.