Have you already changed your light bulbs? If your lights are still not working it is probably your switch.
Watch this video to learn how to put in a new light switch in your 500 Series or 600 Series units and many others too! Below is the link to a generic light switch for most Sub Zero units￼, If yours is the circular variety look for that style￼, They are pretty generic parts and most work pretty well.
Find your light switch here: