I pulled an inoperative C/D player out of the dash and I am attempting to install an OEM radio (removed from my 1st 72 about 1990). I can't seem to seat the radio in the metal bracket because the wiring harness for the fuse panel and another harness for other accessories gets stuffed behind the radio. Does the harness get routed outside and to the right of the radio bracket? I've tried that and can't get enough room to plug in the radio harness. At the moment, I am clueless.

got it figured out. Just need to find where heavy red wire out of heater harness connects to.

The FSM has wiring diagrams that include origin, destination and connector locations.