Try replacing the batteries first, or inserting them the other way. The smaller surface is supposed to face down. If that doesn't work, try pulling out the LED and replacing the bulb. It will take some soldering though. Let me know if you need me to do it for you.
i found that mine was backwards.the small side of the battery(negative) is up.I put them in according to the instuctions and it didnt work.so for the heck of it I flipped them over and no I have laser lites.
An L.E.D. (light-emitting diode) has a polarity (a positive and a negative connection) and it could have been assembled wrong at the factory. Installing the batteries the other way might fix your problem as Boba "awesome bios" mike said. Also take a look at the wires to the LED in the Bio/mask. The wires could be shorted (touching) together, preventing current flow through the LED. If you have access to a voltmeter, you could also verify your batteries are good.
If you prefer, you can work with Sideshow for a replacement. They replaced a broken statue for me without any problems.
I should have mine tomorrow, but had a feeling this might happen as my Dallas and Kane backpacks sometimes work, sometimes don't. Seems that as nice as the Hot Toys LEDs look, they don't always work, which is disappointing.
Email I just got from Sideshow regarding the helmet:
Thank you for taking the time to contact our Returns Department.
We wanted to follow up with you regarding your 14” Predator Exclusive Figure. Please know we are currently waiting for replacement parts to arrive from the manufacturer. As such, you have been placed on a waitlist. As soon as these parts arrive into our warehouse, we will notify you via email that your replacement part will be shipping. We appreciate your patience in this matter!
Please let me know if you have any further questions or concerns.