I’m sure by now you’ve realized that some dousing in contact cleaner, with some Q-tip rubbing can often be needed for ALL these budget lights! But in case others don’t know…
That being said, it seems my new 2016 batch of good-but-cheapies is much higher quality from the get-go than my 2008 barrage. In 2008, all but ONE had quirks (an Ultrafire A6 SS) — in 2016, all but one have WORKED fine when received… Exactly the opposite! Found a metal sliver in that one and now it works! I’ve since done the things found on a sticky in CPF and done them on all my quirky ones from ~2008, and now they *all *work flawlessly as well.
I’ve just recently found and have become infatuated with this light, and although it will replace my old AA EDC pocket light, I think it’s still too heavy for a keychain… For my keychain I found a multi-mode Brinyte PD03A that is super light and quite bright on Eneloops… That way it wont do long-term vibration damage to the key area of the steering column.