Dashboard light is getting dimmer and dimmer

[Learning]

Hi folks

My 91 318i dashboard light is getting dimmer and dimmer. I've already set the brightness adjustment knob to maximum, but my dashboard light is still dim. My alternator and battery are fine and are still like new.
What could be the problem?
Thanks in advance for your answers.

[SmokeE30]

Check the grounds under the dash by the peddles