The 3-speed and 4-speed cars had a dark green wire that went from the clutch pedal switch, through a grommet, and to the starter relay (so you couldn't start the car without the clutch depressed). It doesn't explain why your car doesn't have any power, but maybe it's another piece of the puzzle. Judging from the yellow wire plugged in to the relay at the 7 o'clock position, I'm presuming you have an automatic, but if so, that black wire in the 5 o'clock position hooked to body ground isn't legit. That spot should have the other wire from the neutral safety switch, a brown wire with a yellow stripe. Do you have a wiring diagram?