Someone else asked about splicing lights just the other day. It's not a good idea unless you do it right. You'd want the lights to be wired directly to the battery through a relay and have the led to the switch spliced into the high beam switch wiring. You do not want to use a crimp on splice but do a propper solder splice.
Like I told the other person, it would be better if they went with a DPST switch. This wy they could turn the lights on independantly, turn them off or have them turn on with the regular lights/high beams.