Am I required to fix with similar amenities to what was broken?

[Matt Stoltz]

I recently have a new tenant, and when rehabbing I installed a bathroom mirror with a backlight, that had a glowing ring on the mirror that is used to turn the mirror on/off. After a few months, the tenant has reached out saying that the glowing ring no longer turns on, and is stating that it is no longer functional. However the light still turns on. 

1. I would argue that the small glowing ring, isn't necessary to fix as long as the light still turns on and functions normally. 

2. Could I simply replace that mirror with a normal mirror if she wishes it to be replaced? Or am I required to install a similar mirror with the backlight? 

Thanks in advance for your input.