Super Basic Wire Question: Is there a component allows electricit to flow only 1 way?

[pbMaxLax44]

I know this is probably a stupid question but I have no idea what to look for on google since I don't know the correct term is for everything electrical wise. I know the very basics but have never had to deal with anything besides 12v power, matching colors, and grounding. So, is there a component I can put in a wire that will only allow the electricity (12v obviously) to flow in one direction?

The reason I want to do this is because I put in a few under-dash lights that I supplied power to through the headlights so they come on whenever the headlights are on. I also would like (if possible) for them to come on whenever the dome light comes on. However, I know that if I were to do this it would also make a connection causing the headlights to come on when the dome light is on and vise-versa.

Or if this question has nothing to do with the way this should be done, any suggestions?

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[CHEMMINS 10+ year member]

Yes....it is called a diode.

 

[MANTI5 10+ year member]

You will need to tap into the dome lights to get them to come on with them.

 

[pbMaxLax44]

Thanks CHEMMINS...that's exactly what I needed.

And MANTI5, I know that...I'm not that horribly stupid haha, I've just never had the need to use anything besides wires, head units, speakers, and amps before.