Instrument panel dims and Sony radio flickers when lights are on
 

I have searched high and low for an answer to this question, to no avail. I have a 2002 ML320 with an aftermarket (obviously) Sony touchscreen radio/receiver which was installed a year ago. Everthing worked perfectly during the last year until 3 or 4 weeks ago.

When the headlights are off, everything works as expected. When the lights come on, the display on the radio starts flickering (which is very distracting) and the instrument panel is almost too dim to see. I have checked the fuses I thought to be relevant (the ones in the engine area), but I don't really have the vocabulary to describe the problem any better. Is this common enough for someone to help me identify?

Hello and welcome to the forum! It sounds like there may be a problem with the alternator, as not enough power is being distributed between all the systems.