There is a small bulb behind the fan speed knob, pull the knob out and with a pair of tweasers pull the bulb out and change it.
I had this problem about a year ago. Turned out to be all the bulbs were burnt out on mine. There's 3 (or 4) miniture bulbs that are accessed by removing the heater control.
Have you turned the control from Pilot to On? Have you increased the temperature setting?
Nothing
Perhaps you turned on the interior lights when you were adjusting the headlights?
If you turn up your interior dashboard light settings, then the radio display will be brighter too. The radio dims to the setting for the dashboard when the lights are turned on.
The parking lights are turned on when the headlights are on and you pull out on the light switch. The parking lights cannot be turned on by themselves.
The Traction Control Light comes on every time you turn on the ignition. It should go off as soon as you start the engine. If it does not, then you have the traction control turned off. Turn it back on and the light will go off. If you have the Traction Control turned on and the light stays lit, then there is a problem with the traction control.
For the 1999 Chevy Tahoe, automatic headlights are turned on by default. Turning them off requires opening the bezel on the dashboard and removing the light sensor.
The headlight relay is in the Light Control Module (LCM).
low back, spillage, or a bad thermocouple.
sounds like a bad light switch.
I have a 2006 Pacifica. If yours is equipped with fog lights, grab the end of the left light control tree, and pull firmly. Then, have the parking lights or headlights turned on. You can't have just the fog lights on.