Heater blower cuts out and headlights go on and off randomly

Heater blower will go off randomly. Can restart and will start back up. Have replaced relays, blower motor, and switch panel. Headlights act just as crazy. Second set of aftermarket. Both did same thing. One will shut off while driving, then a different one will shut off. Then both will work for a bit. Thinking both issues are related to a fuse box perhaps? Need help!

 

Sounds like a wiring harness issue. Check where it goes through the firewall.

 

Both my headlights and blower motor have the common underneath hood fuse box. Think a fuse box can go bad?