The yellow dot in the center of the knob lights up when the knob is pulled in the 'on' position
resulting in increased power and enhanced sound
Crankshaft Lower Bearing Shell (Yellow Identification) For Porsche Cayenne (2013-2016) Models
928 (1978-1955) and 944 (1983-1988) models
it helps direct airflow to the radiator
BMW Control Arm with Bushing (Tension Strut) | 2010-2017 94434703323 The yellow dot in theControl Arm with Bushing (Tension Strut) for 750Li xDrive (2010 2015), 750i xDrive (2010 2015), Alpina B7 xDrive (2011 2015), Alpina B7L xDrive (2011 2015), 535i GT xDrive (2011 2017), 550i GT xDrive (2010 2017), 740Li xDrive (2013 2015), 750i (2011 2012), 750Li (2011 2012), 740Ld xDrive (2015)