What does the little knob on my BMW dashboard, not the milage one, do?

There are two knobs on my BMW X5 2003. One cylces the trip mileage and resets it, where as there is one more that if tapped once, something called check control comes on, and when held down, it says Test 1, and then when you push it down it cycles through 23 Tests. I have waited like a minute or 2 to see what it does but nothing shows up or changes on the dashboard.



What does it do and how do i work it?What does the little knob on my BMW dashboard, not the milage one, do?I know on my 3 series it can show things like coolant temp, immediate fuel efficiency, and other not so important stats. I don't know how to work it on the X5 thoughWhat does the little knob on my BMW dashboard, not the milage one, do?It is best left alone by inquisitive owners or aspiring diy mechanics.What does the little knob on my BMW dashboard, not the milage one, do?It's the function test button for the ejection seats.

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