Those are 'surface mount' LEDs. The advantage is that an eventual failure of one does not affect the others and the
light output is only slightly diminished (7% drop if one of your 14 diodes quits).
As none of those 14 are working, and they all stopped at once, I'm leaning towards a simple
electrical, rather than 'electronic', cause.
Use a traditional volt meter set for 12 (or slightly greater) volts DC to test for voltage difference at the black and white wires at that connector inside the light assembly. If you see 12 volts there when the light switch is turned to on (contact closed), then the assembly isn't working. Replace it with a single lamp fixture with a replaceable (LED) bulb.
If there is no voltage at all with the switch in the ON position, look to other, non-lamp assembly (Switch contact? Fuse?) causes.