Hi,If you find they don't light up then definately turn them 180 degrees in the socket.Thats why they would not work for me as a turnsignal indicator because of the polarity switching from the relay.I also found that the led will stay lit using it for the low fuel indicator.Must be a constant low voltage leaking through that isn't enough to light up a filament but is enough to illuminate the led.Couldn't be bothered to check it out because I did find it to be bright enough.Another plus for them is the lower current draw which seems to give a little more reserve to a already taxed charging system.Between the leds(including taillight,license and parking light)and my HID I seem to have quite a bit of more reserve.