Background to white LEDs
White LEDs are essentially blue LEDs with a phosphor in front of them. This is why they look yellow when they are not powered. The white LEDs used in automotive replacement bulbs are generally slightly more blue than the white LEDs used in domestic lighting. It's partly to give a more crisp colour, and probably partly because the phospers used are slightly cheaper…. We have found just as many failures with expensive LED bulbs bought from well-known retailers as with cheaper ones bought in on-line auctions.

The basic LEDs don't appear to be as good quality as individual components bought from UK suppliers, and the bulb circuits are not designed in a way that gives the best component life. This is less of a problem with coloured bulbs as even the cheapest components are fairly good, but the circuit design is still a bit of an issue.

Because LEDs are solid state components, they are much more shock-proof than filament bulbs. When the car goes over a bump in the road, the hot filament in an ordinary bulb can easily fracture. LEDs have no filament, and are essentially immune to shock.

An individual LED used in automotive aftermarket bulbs typically takes 30mA current. They are not the same as the new generation of power LEDs used in domestic lighting, which take ten or twenty times as much current.