Identifying wires

Hey guys, I ran three wires from dash to opening where dome light is to upgrade my flip-down monitor.

I forgot to label which one are which, so I don't know how to identify.

Is there a quick and easy way to send some sort of a signal from one end of the wires to the other, so I know which is which?

I'd hate to have to re-pull them.

Does this make a bit of sense?

Thanks,

 

What are the wires attached to?
are they colored differently?
Do you have a voltage meter?

what does each wire provide connection for? positive/ground... ect.

if the wires are not hooked up at either end, you can test for continuity or even apply 12 volts to one end and test for voltage at the other. careful not to ground out a live wire.

 

Thank you - I figured out how to do a continuity test on my multimeter.