A shop manual for 2003 lists possible causes as.
1. Head fuse (LO LH, LO RH).
2. Headlight dimmer switch.
3. Headlight dimmer relay.
4. Headlight bulb.
5. Wire harness.
You need a shop manual to troubleshoot each possible cause, fuses and the relay are easy. I had a link to a 2003 shop manual but it doesn't show up.
Clifton