which junction box post ?

[Dutie]

Wanna power up my logolite directional signals. Directions says to run the fuse wire through the junction box and connect to the post. I currently have an electric windshield wiper that operates from the left side post from the outside. Can I connect my logolite power wire to this same post to power these lights as well. assuming left side is driver side. Thanks in advance for all replies...... Dutie