Hi @Tides, sorry to hear you’re having issues with your Lumens.
Shorting the (yellow) signal wire to the (red) power wire sets the lights to full brightness. It’s possible to have control over the brightness by providing a PWM signal to the yellow wire, as specified on the product page.
That said, when the lights are daisy-chained they should operate together. If only one light is working then there’s likely an issue with the other light, or the cable between it and the first one (assuming the failing one is second in the chain). I would recommend you contact support@bluerobotics.com to determine what is wrong with your light(s), and to sort out a potential replacement or refund as relevant.
Potentially, depending on the nature and extent of the damage, and assuming the cause is able to be determined. Not every problem is repairable, but if it’s determined that a partial replacement would solve the issue (e.g. a cable, lens, PCB, etc) then we can likely send the part(s), assuming it’s something we have available (e.g. we generally get PCBs populated by a supplier, so we could send a replacement PCB but likely not a single capacitor or microcontroller).
Note that if you’ve received a faulty product from us then we’ll make sure you’re provided with either a partial or full replacement, or a refund, depending on what makes the most sense for the situation.
I’m not sure what you mean by this - the only way “shorting them” could be detrimental is by shorting one of the wires to an external signal or voltage it’s not able to handle. Shorting the light’s wires to each other will either turn the lights on (signal to power), turn them off (signal to ground), or provide no power (power to ground).
If you’ve provided a negative/reversed or overly large voltage then some components may be damaged, but it’s not guaranteed which ones, and may not be simple to determine. The simplest repair in that case would be replacing the PCB.
If you’re electronically inclined and want to replace individual components then you can find out what they are from the schematic on the product page, but would need to source them and any relevant tools (e.g. soldering iron, cable insertion tool, etc) yourself.
Opening our lights should not affect the depth they can operate to (in the same way that opening an enclosure doesn’t), but you’ll need to be careful during re-assembly to properly clean and lubricate the o-rings and flange, and properly tighten the penetrators and screws.