Hello,
Has anyone had issues with one of their side mirrors not defrosting? The defrost button used to have 2 lines light up when on and only has 1 lighting up now. I hope it's just the fuse that needs replaced. Please Advise.

 

Although anything is possible, Usually if part of the mirror is defrosting it would indicate power is getting to the heating element within the mirror glass, so a fuse is removed as a possibility. It would be a good idea to confirm sufficient power and ground are available to the heating element in the mirror and if so , the glass portion would have to be replaced.