Jim, my car is a bit older but I hope this wiring is similar. Unfused power (from the hot side of F3) goes to the headlight dash switch, then to the main/dip beam switch. Both the main and dip beam outputs go through fuses (F1 and F2) to the respective light connections. The head lamp flasher switch gets power from F8 and connects to the dip switch main beam output.
Turn on your headlights and check for power at both terminals of the headlamp switch. If neither shows 12 volts, the trouble is with the connection to F3. If only I terminal has power, the switch is defective. If both have power, the problem is with the connection with the dip switch. Because the flasher works, all of the rest of the high beam wiring is OK.
I have found, when working on my car, that the fuses have been reassigned and are not in agreement with the shop manual schematic. The schematic included with the owners manual was more accurate. Good luck, Bill Braun