I know it doesn't sound right, but check the bulbs in your gauge cluster too. They very rarely go out at the same time, and for that very reason I drove around for a few days unable to figure it out. But I ended up just taking it out for the hell of it and whaddya know, two of my bulbs had burned out at the same time. Or, perhapse, one had burned out and I didn't notice until the other went out leaving me with no light at all. This was in my daily driver integra BTW, which has two main bulbs lighting up the cluster. I haven't had to check the ones in my 3Ss so I'm not sure if it's similar to what you are describing, but worth noting.