I have replaced my stock headlight with the HD Daymaker LED headlight, with a modified NAMZ headlight adaptor harness to go from the H4 to the 4-pin connector.

Whenever I turn on the hi-beam lights (either with the toggle switch or passing switch) the headlight turns off for a split second, then immediately returns to the lo-beam light.

With the HD Daymaker LED headlight or no headlight connected at all, the same results occur. When lo-beam light is selected, there is 12V to the lo-beam, and 0V to the hi-beam contactors. When the hi-beam light is selected (toggle switch or passing switch) there is 0V to the lo-beam, and 12V to the hi-beam contactors for a split second, then the voltages flip back to 12V to the lo-beam, and 0V to the hi-beam contactors.

With the stock headlight, everything works perfectly fine. When lo-beam light is selected, there is 12V to the lo-beam, and 0V to the hi-beam contactors. When the hi-beam light is selected (toggle switch or passing switch) there is 0V to the lo-beam, and 12V to the hi-beam contactors.

Has anyone experienced this before or have any suggestions? The fact that everything works perfectly fine with the stock headlight indicates that there are no grounding issues, or other wiring issues from the BCM or switch.

Motorcycle: 2012 HD Fatboy Lo (FLSTFB)

Stock Headlight: 7” OEM HD Single Headlight (PN: 67700060)

LED Headlight: 7” Daymaker Projector LED Headlamp (PN: 67700060), NAMZ OEM style LED Headlight Adaptor Harness (Daymaker) (PN: NHD-69200533)

2012 HD Softail Headlight Wiring Diagram

Daymaker LED Headlight

Stock HD Headlight

Stock HD Headlight Connector