3STTW

The box that they added was probably an LED driver circuit. So let's have a nerd moment; an LED driver provides two functions: 1. Incandescent light bulbs are constant voltage devices, i.e. if you put ten of them in series in a 12v circuit, you would need to apply ten times the current to get each one to emit the same brightness as a single bulb in the circuit. The opposite is true of LED's; if the forward current of a single LED is 1 Amp, even if you put 10 in the circuit the current needs to be maintained at 1 Amp, however you need to increase the voltage in order to get them all to switch on. So LED's won't work well with a fixed 12v system and this is why they need a constant current driver. 2. If you keep LED's switched on all the time, they don't last long because they aren't very good at dissipating heat. The best way to increase their life is to have them switched off half the time, if you switch them on-off 20 times/second this is what happens in practice. The LED driver takes care of this, it also explains why when you shoot a video of cars at night their lights appear to be flashing - this is the stroboscopic interference between the LED drivers' switching frequency and the camera shutter speed.