I have been having weird headlight problems with my RK. The head light will quit working for no obvious reason. Static testing with an Ohm meter doesn't reveal any problems and the weird part is, when I remove the seat, the light comes on and stays on for awhile and then days later, the problem repeats. Handlebar switch seems ok. Maybe its an issue with the ignition switch. Anyone have any ideas?

 

I wouldn't think it's an ignition issue if the bike continued to run but that's only shot in the dark

 

welcome to the forums.

1st check the headlight socket isn;t melted or heat damaged- or corroded contacts.

high and low? then follow the black wire for ground and make sure you have a good ground connection to the triple tree.

any fixes done to wiring over the years?- if so look there first, soldered joints do not hold up to vibrations

then it's check wiring from fuse to headlight switch- i don;t have a wiring diagram for your year

evo models had a problem where high wattage bulbs would burn out the ignition switch- I think they changed that before 2003
wiggle ignition switch, any change?

mike

 

OP says that when he removes the seat, the light comes on. Doesn't the wiring harness sit very close to the seat at the rear of the fuel tank. Just a guess but maybe a pinched/broken wire in that area that gets moved when the seat is in place. Try taking the seat off. Then try pushing/moving the harness to see if you can make the light go out. It should not be a short to ground otherwise it would blow the Lights fuse. I don't have the wiring diagram in front of me but many times HD uses a Orange/White Stripe wire to bring power to the lights.
You could also try checking for power at the headlight plug the next time the headlight fails before removing the seat.

 

That is where I would start but also remove the tank console. The problem may just jump right out at ya. Could even be a loose connector under the console.