2006 Cadillac DTS - Aftermarket audi issue

I have a problem (conncected???) with a Pioneer radio/cd (not factory installed) which plays super well, for a few minutes, then will go to terrible scratchy background and can barely hear radio. Some silly thought makes me wonder if it and headlights are somehow ‘enemies’. If I turn radio off and then back on again, it starts out fine again, only to revert to scratchy. Sometimes it’s as long as 12 minutes good, and sometimes only 2 minutes and variously, anywhere inbetween. Can you offer suggestions as to what to even check? Thank you.

No recommendations on what to check, only what to CHUCK… the Pioneer radio. Far more likely the problem that anything on the car.