I have a late 90's softail. my headlights work fine on low, but when I turn on high beams, they go out. Blinkers stay on and no other issues. I know pretty much nothing about electronics and dont know exactly where to start.

 

First thing to check is power at the headlamp connector. Remove headlamp, unplug the light from the connector. Aquire a twelve volt test light. Ground test light and check that it lights on a known twelve volt source. (ie the pos. of bat.) Then take and check power at the headlamp connector. Turn on ignition like you were out on the road and check headlamp connector one wire should be lighting up the test light. Thats the low beam power. Switch on your high beam switch and one of the other two wires should light up the test light. If two wires are lighting up your test light then your headlamp needs to be replaced. The third wire is the ground for the headlamp.

 

what if all three of my headlights are doing it? do you think if would be further down in the system?

 

The low beam and the passing/spot lamps will work together. As soon as you go to high beam the passing/spot lamps will go out because of the way its wired.

Did you check the power at the plug???????????????????

One step at a time.