Tempermental light behind the air vent location switch

[1997Camry]

THis is the '97 Camry, and as you know there are 3 switches controling air. From left to right, fan speed (off/1-5, air temperature (cold to hot), and vent air direction (front, upward, downward, windshield).

My problem is with the light behind the vent air direction selector. When I turn on headlights, that light would remain dim even though the lights behind the other 2 switches light up. Then when I turn the switch, ie. from front to up, the light would come right up. I've noticed it on half dozen occasions, and this just started to happen within past month. The lightbulb seems to work and it maybe somehow electrical contact or other problems there. Any ideas? Thanks in advance.