When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The "blank" is next to the steering wheel. It's where the rear defroster switch is located on '02+ cars.
Looks like you have (or had) a hardtop installed. The first switch is for that defroster (this was the solution in pre-'02 cars.) In europe the switch to the left is for the headlight washers.
Stock USDM S2000s just have an empty space where that switch is. It's generally referred to as the "coin cup."
Sorry, this is the best pic of the coin cup I can find.