I am trying to add a new timer switch and standard single pole light switch in my bathroom. Both of these are in the same metal switch box. I drew a diagram to help myself understand what I am looking at. I omitted the bare ground wires which are attached to the back inside of the box.
Here is my understanding so far:
1.) The light switch on the right seems to be using a 3-way switch given that there is a brass screw and two other unused screws (that don't appear to be for grounding screws due to their silver color).
2.) I assume the power for the light comes in through one of the cables at the bottom right of the diagram and the blacks are pigtailed together to provide power to the other cable at bottom right and to go to the light switch. When the switch is flipped power continues to the light through the black wire at top right.
3.) To change the switch I should be able to connect the two black wires currently connected to the switch to the two screws of the new switch. Which black wire I attach to the top and bottom screws shouldn't matter. I am swapping out the old switch for a Leviton single pole switch.
Is that right?
The left side of the box is a puzzle to me. The fan is marked "Line" and "Load" on the screws on the right side of the fan timer. Can someone explain how the power flows and is controlled with the fan timer?
I opened things back up and took some pictures. I have not changed anything since originally taking off the cover plate. I believe my diagram was basically accurate, though the unused screw on the light switch was on the right side of the switch and not the left as I had previously drawn.
I also noticed that on the fan timer the wires pass through the timer and connect to screws on the other side. So "LOAD" and "LINE" based on what the timer said are actually revered from my original diagram. It's hard to get a good picture but the black wire passes through the timer box and connects to the screw on the top left side of the box marked "LOAD 1".
Also, having looked closer I believe the the fan is controlled by two switches. There are two bathrooms right next to each other and I think the switch in either bathroom will control that shared fan.