it's the headlight switch if the wire terminal is corroded or a broken wire there. if the lows work and not both the highs, then it's the dimmer or wires . a stock harness (which we don't know what he has) has the same fuse for all.
unless he has what some of us have
a separate circuit for each. i run two relays ... one for each Lo/Hi beam
it's easy to trouble shoot.
Last edited by carolines truck; 01/19/2009 4:37 AM.