The seller is conveniently leaving out several emails in which I asked for further help and he either didn't reply or directed me to the wrong place (repeatedly) to find the information or told me to just ignore the fact that the light doesn't work.
I have purchased many things online, from laptops to my current vehicle to a pack of gum and this is the worst customer service I've ever received.
The bottom line is this: the unit doesn't work properly and the seller's reply (more than once) was that "sometimes this happens" and not to read anything into the fact that the power light doesn't come on or stay on most of the time, even after fresh batteries have been installed. If the power light isn't important, why is it part of the assembly?
This is just an excuse for crappy quality and top-of-the-line prices. I wish I'd ordered one of your units, Parazapper -- people seem to be happy with their quality.