How do I fix bathroom fan which is not working?

Question

I recently moved into a new home and found out one of the bathroom fans don't work but the lights are fine. I thought at first it was the motor but the motor run if i connect it directly to a power socket. I also tested the wires on the exhust fan and they have no current. I tried to understand the wire but I have not accomplished much. Usually there are only two sets of wires but in mine there are four. I have checked other switchs and there not the same there simpler. I have taken a picture so it will be easier to help, i have included a picture what i know or think i know.

1. Basically the first wire form the left is the form the light.(Black/White)
2. The second wire is the power line. (Black/White)
3. Not sure what the third wire is. (Black/White/Red)
4. Not sure what last one is either. (Black/White)

If anyone has seen this before please let me know.

Labels in the picture.

M-Line : Main power T-Wire : Transferring Wire, this wire provides current to both switch.

Any help would be appreciated.

Answer 1

Without actually being there, and not being able to see the wiring at each of the devices, it's difficult to be sure what's going on. But here's my best guess, based on past experience.

To make it easier, I've numbered the ungrounded (hot) conductors in the photo from left to right.

1. You've already established goes to a light.
2. Supplies power to the switches.
3. Likely goes to the fan.
4. Also goes to the fan, but since the fan doesn't have a light built in, it's likely capped off at the fan.
5. Probably feeds some other device, maybe a receptacle.

Why 3 and 5 are controlled by the same switch, I have no idea. Again, I can't see the room, so I have no idea what equipment you have.

If 1 and 4 are both for lights, it makes sense that a singe switch controls them.

One other thing to check, is to make sure the terminals of those switches are rated to accept more than one conductor. There should be a label on the switch that tells you what type, and how many conductors can connect.

Answer 2

Without any of the information that I asked for in my comments. I'd say the 3 wire (black red white) most likely goes to one of the fans or the light box. The light box if both fans are fan only. Check the right hand switch and the make up in the light box especially if the light looks new . Someone may have replaced the light and left the red wire at the light box disconnected from the wires feeding the fan.