Also known as BAY12D 12V 21/5W Brake and tail light. Available aftermarket:

SCA Automotive Globe - Stop/Tail, 12V, 21/5W, 2 Pack - Supercheap Auto Australia


How do I know this? Because my 2011 Caddy uses them for the daytime driving lights . . . correction, chews them up and spits them out every 6 months because the filaments in the bulb are not designed to be constantly on as daytime driving lights, overheat and burn out.

So I get myself some aftermarket LED versions, then find out the hard way that they are not CANBUS compatible. Luckily I have just found some on ebay that are CANBUS compatible, so will be giving them a go.

On the subject of light bulbs, the design of the side-light bulbs in the Golf Mk5 means that without specialist tools or go-go gadget fingers it is impossible to replace one.