Grounding Issues ?

Changed relay for driving lights on my 99 Beetle, driving lights still not working. Been using brights at night. Checked fuses all seem good, also have one brake light not working. Feeling like it could be a ground issue. Brake light fixture seems to have heated up also wire for headlight seems to have heated. Bulbs are good. Over time there have been some smaller issues. Dome light kind of works whenever it wants (I never change the setting). I have found where the negative connects from battery to engine but where is the ground for the instruments? Is there another ground or how does it ground the rest of the car? Any advice would be appreciated. Thank You!

3-4 grounds underneath the battery tray. Pull the battery, then the tray.

Thanks

Still have electric issue Driving lights not working, left brake light also. Yesterday I changed my starter and now my dome (interior lights work) any suggestions will be deeply appropriated. Changed the relay for driving/head lights no improvement