Im just about finished switching out my gauge faces and changing out all the bulbs and leds over to blue. The process has gone smooth, however the white led's (PLCC-2) I bought to light up the needles in the speedo and tach don't work. I replaced the white leds with blue (PLCC-2) leds and everything works as it should so I'm confused why the white PLCC-2 surface mount leds didn't work, but the blue ones do. Any ideas??

 

Just a thought, is it possible the diodes you have are reverse biased. Despite purchasing from a good source their supplier may have shipped an incorrect batch. Easy enough to check one not installed

 

Thanks for he suggestion hoakken, that crossed my mind as well so I tried switching them around, still no luck though.