Xenon Headlight HID Ballast/Control Unit 1307329153 130732915301 for E92 E93 328i M3 X3 X5 S TT R8

OE / OEM Number: 1307329153, 130732915301, 1307329193, 130732919301, 63117182520, 63112754797, 8J0907391, 25806714 Fits: 2007-2013 328i 328xi 335i 335xi M3 (E92 E93) Coupe or Convertible Only; 2008-2011 M3 (E90); 2007-2010 645Ci 650i M6 (E63 E64); 2007-2010 X3 (E83); 2007-2011 X5 (E70) Fits: Cadi-llac DTS 2007-2011 (NOTE: Multiple ballasts are used for this model. Your existing ballast should say "307 329 153" or "307 329 193" on it); 2007-2011 Au-di TT (NOTE: Multiple ballasts are used for this model. Your existing ballast should say "307 329 153" or "307 329 193"); 2009-2012 Au-di R8 The first function of a ballast is to help your lamp light up quickly. When the lamp is turned on, the ballast provides a higher voltage surge to the lamp. This helps to establish an arc between two lamp electrodes, which is what causes HID bulbs to light. The other key function of a ballast is to keep the lamp on and make sure the output is stable. A defective ballast causes the total failure of the headlight. The causes of ballast failure include: 1. Lack of voltage supply; 2. Lack of ground connection; 3. Defective electronics in the device; 4. Internal shorts