The light behind my temperature control knob is out. At night, I cannot see the blue/red lines. Good thing I know what side each is on. Temperature can still be adjusted. However, if I try to change to 'recirculate air' the small yellow light flashes and then goes back to the light for 'fresh air'. Each not vital but a nuisance at this point since I don't use recirculate in the winter. Can this be repaired? Is there a bulb behind the panel? I don't see a fuse for this problem.