The dark green temp wire runs through the engine harness from the bulkhead connector under the brake booster, from the bulkhead to the gauge connector on the back of the gauge set through the dash harness. It comes out of the engine harness near the exit point for the wiper motor wires. There may also be a tan wire that runs out with the temp sender, this is the engine stop solenoid on some applications.
For 70 and 71 only, the brown tach wire comes out of the dash harness near the center of the dash, through a firewall grommet near the windshield wiper motor then to the negative terminal on the coil. On most other years, this brown tach wire will run through the engine harness.
Here is a picture of the connector on the printed circuit board on the back of the gauges. pin 10 is the green temp wire. pin 9 is the brown tach wire.