I know this is reviving an old thread but just wanted to share my experience.
I had the same issue with a set of heated Truck-lites seemingly only heating the top section of the light.
I may might have been hyper sensitive to the "heated" piece, but when the lights are being advertised as
"Heated Lens’ provides a steady, complete surface melting of snow and ice, only active when temperatures drop under 50˚F" I wanted to check with Truck-Lite themselves. I initially thought like some others that maybe there were 2 different heating elements, one for the top (low beam) and one for the bottom (high beam) that only activated with the corresponding beam, but that was not the case. After a couple of emails back and fourth with several different techs, and some interesting responses from internal emails such as
"This looks fine to me but I’m unsure what they’re supposed to look like.", the warranty department confirmed that the light should heat completely and uniformly and are issuing me a replacement set of lights.
If you are seeing only the top half of the light defrost it maybe worth a quick note to Truck-Lite. The warranty department also shared this tid bit of information,
"There was a design issue with the initial samples that were built about 1 year ago". Unfortunately they also said that there was no way to identify the lights that would have been in the lot that contained the defective units.
Thanks Truck-Lite for standing behind your product! :thumb: