1999-2004 Honda TRX400EX FourTrax Service Manual, Page 248Get this manual
LIGHTSSWITCHES
BULB REPLACEMENT
HEADLIGHT
Remove the front fender (page 2-2)Remove the dust cover from the headlight
DUST COVER
Remove the bulb socket by turning it counterclockwise while pushing it inReplace the headlight bulb with new oneInstallation is in the reverse order of removal