So I just noticed that when I step on the brake pedal and the headlights are not on that all my interior/gauge lights dim. Also when I dont have the key in the ignition and I step on the brake pedal that my interior/gauge lights turn on very dimly and the beeper indicating that I left my headlights starts to beep but my headlights are not on?

I've checked the battery terminals and theyre tight and also all the grounds looks fine as well.

Any help would be much appreciated. Thank you in advance.