Need help with my 84 Chevy Scottsdale truck

[Hollerboys92]

My dad has a 84 Chevy Scottsdale truck the headlights and the tail lights and the dash lights are not working but the turn signals work if anybody can help please let me know

 

[rancher1913]

check and clean the ground connections. the tail light are inside the housing and also from body to frame, the headlights are by them. the main is above parking brake, easy to get to if you pull dash panel and ac vent, its right behind vent. do the battery grounds as well, one to motor and one to frame