Actually the first answer above is incorrect regarding the low beam lamps. The low beam bulbs do have two filaments – the low beam (full power) filament and a low power filament which switches on when the high beam circuit is selected. The low beam filament goes out, and a lower power filament is activated. With the high beam lamps illuminated, the low beam bulbs become marker lamps.
Ron Francis offers a “Headlight Brightener” jumper which keeps the full power low beam filament illuminated when the high beam circuit is selected:
https://www.ronfrancis.com/prodinfo.asp?number=BJ-2I had enough left over parts to make one of these myself and it works as advertised:
http://imageshack.com/a/img706/1296/jumperharness004.jpg
