I am in the process of updating some light switches in my home and I encountered a single pole light switch with 4 wires attached to it. It is the light switch on the right in the diagram.
This light switch is inside a bathroom and these two switches control a fan / light combo, and vanity lights. The switch on the right controls the vanity lights and the fan, so I assume that is why there are two wires attached to the top (B4 / B3).
B2 is the hot wire and it loops around the screw and jumps to the switch on the left.
B1 is a wire that comes from the box and is backstabbed into the light switch. I tried removing it from the light switch and the outlet inside the bathroom lost power. I assume that they are just using the light switch to make the wire hot instead of adding it into the wire nut?
Would the fix for this to add B1 to the pigtail with the black wires?
Thank you in advance for your help.