Further to my original post above, it seems some US-Spec bikes do not have a flasher relay that's capable of dealing with all four lights being activated at once. The flasher relay is located just in front of the battery and there should be markings on this relay looking something like "T: 21Wx2" and "H: 21Wx4". So if you exchange the handlebar, or install some sort of switch to do the four-way flashers, you may also need to upgrade your relay.- Older US-Spec DL1000s do not have a switch on the handlebar to activate hazard lights (four-way flashers) and flash-to-pass. If you exchange the left handlebar cluster for a Euro-spec one, or to a later model US-Spec one, you get the hazard switch and the flash-to-pass trigger. All the wiring is already there, it's just a matter of getting a left handlebar cluster with the proper buttons.