My VW Polo 6R left tail light is off and it seems there are several kinds of bulbs available for purchase:

12V 5W
12V 12W
12V 5W + 12V 12W
12V 12W + 5V 5W

My first guess is that the 5V is just a mistake on the listing. But what are the bulbs that are listed as a combination of 5W and 12W for ? Do they draw different currents when the engine is on/off ?

  • 1
    Are you sure it is 12W and not 21W?
    – HandyHowie
    Commented Oct 23, 2019 at 10:02

1 Answer 1


If it is a 21W/5W bulb, then it has 2 filaments of different brightness.

The 5W filament is for the side/tail light for night driving.

The 21W filament is for bright illumination when you press the brake pedal.

Image copied from ToolStation

Image copied from ToolStation


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