Are both the right and left lenses in this image supposed to be lit when the running lights are on? Or just one of them?


Left taillights '99 Civic

 

Running lights, both.

Brake lights only outside lens.

 

Yes. And turn signal should light up yellow in the bottom outside, reverse lights up white in the bottom inside.

Also always check the two little bulbs for the license plate, that's an easy ticket.

If you can't get any of the running lights on the trunk lid to light, that's likely because the wire that feeds them has broken where it flexes every time you open the trunk.