Not sure about the UCE setup...Hell, I'm not even 100% clued in on my own "Iron Belly's" layout...but I do know that my 2005's has some cockamamie dual DC and AC rigging whereby the headlamp operates directly off the alternator and hence only when the motor is running, and not off the battery. Accordingly, I have noticed that its old halogen bulb dims just a bit when at idle, perking up once the revs do. My guess is that an LED headlamp bulb might shine more steadily, but rarely ride at night, so haven't yet bothered to swap it.
I also removed that mandated "dogbone connecter" in the headlamp shell overriding the switchery that once kept my lights always-on, so my lighting switch on the handlebar now works as it should--Just because having a "nuttin' button" there bugged me. Somehow, I manage not to forget the lights, though it matters little towards juice conservation's sake now that I've yanked out that flakey starter sprag rigamarole and gone kickstart only, as the Lord and Redditch intended.
One bit of advice: if you're still using replaceable halogen or other incandescent bulbs in a non-sealed beam shell, do try not to touch the bulb itself with bare fingers. The oils, decades of cheetos dust, and so forth from your fingers will greatly hasten its burning out. Hold it with a kleenex or similar. And if you DO touch that bulb (and come on, you know you will), then just wipe it clean with a bit of isopropyl alcohol.