[77 K20]

The two inner lights(on the tailgate) have dual filament (5/21 Watt) bulbs, but only the 5W filament is connected, which is why when we press on the brake pedal, only the two outer ones light up as brake lights. What I'd like to do, is to wire up that 21 Watt filament, on both sides for that matter, so that they will act as two additional brake lights, for a total of four. I personally believe that this will act as an added safety feature when braking and advertising this to any followers from behind. I'm still at a slight loss why VW did not do this from the factory, when North American B5.5 Passat models (2002-2005) had all four circles light up not only as marker lights, but as brake lights as well!

Been doing reading on this forum to learn more and hate to dig up an old thread like this, but I have an answer to the above question.

Euro regulations state that a rear fog light cannot be closer than 4" to the regular brake lights. So they disabled the inner brake light so it would not interfere with the rear fog light (that the US didn't get).

I have a B5.5 Passat and looked into adding a rear fog light to it. It is goofy- in order to do so you need to buy the euro taillight housings. The US spec ones have 4 light circles on them and they are lit by 4 light bulbs. The 4" rule doesn't work with this housing. So the euro housings split every circle in HALF (upper half vs lower half). So you have 4 circles, but 8 bulbs to light them up.

In Euro cars the brake lights only light up the top HALF of the top circle. This then gives the 4" distance so a rear fog light can light up the lower half of the bottom circle (on one side).