Thermador Gas Range Over On Indicator Light Not Working

Thermador 30" all gas range (PRG304GH). Everything works fine, except the blue "Oven On" indicator light no longer works. The oven works fine, and the cooling fan comes, but the light letting us know the oven is on never lights anymore. 2.5 years old. Other indicator lights (e.g.cooktop indicator lights) work fine. Any ideas? It is easy to disassemble the top to see if there might be a loose connection somewhere?