70 duster question

i just aquired a 70 duster theres 3 main plugs in the firewall the front harness plugs into two of them and the drivers side theres nothing pluged into it would this plug be used for the heater wipers heat gauge oil pressure gauge scince i see no wires for these items if so where can i get this part of the harness 70 duster with the rally dash i hope this makes sense thanks all i tryed to send a pic with this but it said file was to big thanks