A common problem ive noticed with the rear led brake light not working and after stripping mine out it looked liked one of the diodes on the lamps circuit board had cooked its self, i thought about buying a second hand one but there's no guarantee as to how long this would last so i thought id give it ago and fix myself and if it all went wrong a second hand one it is.
i started off by removing the 3 screws which attach the brake light to the spoiler then undoing the wiring plug and removing the light unit from the spoiler, the unit is complete ie the red lense is glued to the black housing, i got a small screw driver and started to prize the red lense away from the housing whilst gently easing the lense away as i went along to prevent it from cracking (starting at one end) and as can be seen in the pic it seperated ok.
the led circuit board is attached by a furthur 3 screws to the housing which were undone,i then cut the wiring plug off as close to the circuit board as possible as this is needed later on.
My £2.99 replacement 48 LED light unit was purchased from ebay and this too was seperated which was easily done (the ebay item is about 4 led's short from the nissan item)
with the above ebay item its just a simple case to cut the wiring and attaching it by soldering it to the nissan's wiring plug,the ebay led circuit board was then bonded into the nissan's housing to keep it in place,the nissan's red lense was then re-glued back into place using superglue.
Job done.
