You're going to need the fuse box diagram/layout for your vehicle. It should be readily available with a Google search then click on images and match up your box layout. A few should have a description along with the fuse number. There are often more than one fuse that can be associated with your issue.
Also an aftermarket alarm, depending on its wiring, can have an effect. the previous owner of my X has about 5 fuses tied into the alarm that affected the headlights. Not professionally installed.
I've had to troubleshoot some issues with mine and checked every fuse, a total pain.