Heater Control Panel Removal-73 Dart Sport

It just light up the slots where the controls come through. Its a really dim light but it does allow you to see where the controls are when its dark.
Its been a long time so going off memory. I think there is a metal bayonet base bulb holder mounted on the back of the control panel. You might try reaching up under the dash and see if you can feel it. Like I said, removing the glove box would give you good access.