You can easily replace it but you need to know why it blew in the first place. All fuses are marked on the fuse box or in the drivers manual as to which circuit they protect. Determine which circuit that blown fuse protects and inspect that circuit for troubles.
What do mean fix it? Have checked the fuse has not blown?
Replace
Fuses cannot be fixed, only replaced.
This is a blown brake fuse check your break fuse and should fix it.
most likely it its fuse blown out. replace the fuse if it is.
Check for a blown fuse.
How do I fix my cigarette lighter when fuse is good
look for a blown fuse.
Check for a blown fuse.
Sounds like a blown fuse?
Look for a blown fuse.
Blown brake light fuse.