You have to replace the whole light. I doubt anyone has the OEM part number for it laying around, but this should help. Requested information. You can also it get the number with a quick call to the nearest stealership, along with a price quote for comparison. That should be the left lamp. It will cost more if it's the HID light vs the Halogen. Also, that $500+ quote in the link above is waaay out of the ballpark.