12 Volt feed

[MacCamper]

I am a total newbie to full-time RVing and my problem is I’m trying to find a 12 V feed in imagine 2600 rear bathroom for a composting toilet fan I’ve tried the light switch see going to the 12 V light but when I connected the wires and turn the composting fan on the lights came on also. I tapped in the new wire before the light switch so I was very surprised when the light came on also. Any thoughts or suggestions will be very grateful.

[jkwilson]

How much current does the toilet need? You have to consider wire size and fuses.

Running a new set of wires is not a horrible job.