It takes two relays to get high and low beam. Rick has it right- - - -run a heavy wire from a good battery voltage source like the starter cable terminal to somewhere on the core support near the headlights, and wire it to both relays- - - -terminal #30. Wire terminal #87 of one relay to both high beam filaments of the headlights. Wire the high beam output of the dimmer switch to terminal #85. Wire terminal #86 to a good ground.
Low beams- - - -connect terminal #30 of another relay to the heavy wire from the starter cable. Wire terminal #87 to both low beam headlight connectors. Wire the low beam wire from the dimmer switch to terminal #85. Ground terminal #86. Now all you need to finish the job is a heavy wire connected to the ground terminal of both headlights to a good ground such as the frame or the body, or even back to the grounded battery cable. Use at least #12 wire for all the power and ground connections for the sealed beams. Smaller wire can be used from the dimmer switch to the relays, since the dimmer and the headlight switch will only be carrying a couple of amps of current to energize the relays. All the heavy current is carried by the big wires to and from the relay contacts. The same terminal numbers are used on both 6 and 12 volt relays.
The park and tail light circuits from the light switch will remain unchanged.
Jerry
