Should Be Fibre Optics. The Optic Cable Reflects Light From The Source. Also I've Seen The Lens On The Fender Covered With Wax Or Dirt. Try Cleaning First. If No Better, Ck The Parking Light Housing For The Optic Line Being Secure , Also Ck The Optic Lines Behind Each Headlite. Sometimes They're Mis Routed Or The Tip Of The Line Is Dirty, It Wont Reflect The Light Up Thru The Line To The Fender Lens. Actually A Very Simple System, As Long As The Line Is Pointed At The Light And Clean On The Tip And Not Kinked It Is Trouble Free. Hope This Helps, Bill.