fuse panel on firewall side

[69chevytrucker]

i have a problem i took my truck apart 2 yrs ago trying to put back now i dont know what is missing on my harness on the firewall side it is square i have the piece with the bolt and it has wires for head light alt etc but the harness looks like it is missing something else that plugs into the panel anyone got pics or can tell me what the plug looks like cause there has to be 2 things that p lug in on firewall side hope i explained my problem right lol any help would be great
thank you