The most probable cause is a low battery if the vehicle is not running. But this may be "normal" for your unit. If this happens when the vehicle is running, you might need a quick check of the electrical system. The headlights draw a lot of current, and this will cause the voltage in the electrical system to "sag" or "dip" a bit. In a small lamp like an interior light, even a few tenths of a volt less "drive" on the lamp can be noticed. No panic here, but maybe put a voltmeter on the battery when the vehicle is running to make a quick check to be sure the charging system is working.
sounds like you need a new head light switch
on the left side of dash board there is a little buttom push it in it will pop out turn it to either brighten dim on turn on interior lights
Projectors usually become dim when the "lamps" are running out and they need changing. To be honest I would suggest changing the lamps every 6 months to ensure that the lamps do not run out.
First guess would be a bad switch.
We light candles and dim our dimming lamps.
In a 1997 Lincoln Continental : To the right of your headlight switch in the dash is a ( panel dim ) switch I believe if that is turned all the way up then the interior lights will come on
You probably turned them on by accident. They are controlled with the same pull switch that turns on the headlights. By twisting the switch to the far left it will click and the dome lights will turn on, by twisting it to the right it will turn off the interior lights and will then dim the dashboard lights.
Your insturment pannel is currently set to auto dim. page78 in owners guide
Yes, if you have dual beam lamps.
The rule of the road is to flash your high beams to remind them to turn their high beams off.
The alternator may be on it's way out.
If your interior lights are dimming, either your battery or starter could be failing. You should have your car checked.