X5 Tail light - I'm puzzled

[UrbanFlow]

Hello all,
Can someone explain why the middle tail light bulb (between the turn signal at the top and the tail/brake light at the bottom) is a dual filament bulb whilst the bottom one is a single 21w bulb and has dual functionality?
- I'm confused!!

[powers1]

Originally Posted by UrbanFlow

Hello all,
Can someone explain why the middle tail light bulb (between the turn signal at the top and the tail/brake light at the bottom) is a dual filament bulb whilst the bottom one is a single 21w bulb and has dual functionality?
- I'm confused!!

This has been talked about here a few times,but its easier for me to tell you here.
I know its confusing as we are used to thinking that dual filament should always be the main brake bulb,as it in fact is in most cars!
However,in the X5 the single filament lower light bulb is your main brake light.The middle bulb is also am "emergency" brake bulb,only works under really heavy braking.Get someone else to drive the car and apply the brakes heavily and you should also see the middle light bulb light up as brake bulb

[UrbanFlow]

Ah thanks
That's all clear now!