Hello & welcome to the SMC discussion forums,
the “Have a Coke” lamp is a basic night light sized incandescence bulb usually between 4-7 watts & 120 volts with a edison type candelabra screw base, the size is often referred to a a C7 lamp, however a 120volt/6watt/S6 lamp is also used in these machines as it somewhat smaller size fits better in tight indicator type lamp holders, as the C7 size is quite a bit bigger in diameter. ... it is controlled by a switch down at th bottom of the bottle vending stack, if it’s not lighting up after you put the correct amount of coins in the machine, I’d start there.
Is the Bottle port light ( you referred to it as the Cold bay” light
... is it located at the top or along the side of the bottle port ? If at the top, it’s the same as the “Have a Coke “ light but it gets its power from the wiring harness inside the coinmech socket area usually on most ‘60’s machines.
If it’s along the side it’s probably a florescent light behind a glass or plastic protective window. Some (as previously mentioned) use a starter and Ballast setup, but some economy’ models still used a manual “Push to start” switch located typically just above the inside/top center of the bottle port, if all of the components are good, you just push & release th switch until the lamp lights up.
Sorry if the explanation sounds a little academic, but I like to be technical. Again welcome to the site ( both of you) & stick around, we have fun here