2001 cls r. side low beam initially required 2 attempts to turn on, then began to flicker. 3 days later would not turn on at all. changed bulb -did not appear to be burned out- and burned out fuse but no effect. Fuse burned right away, replaced it and burned out again..could it be the ballast?

 

Switch the ballasts between both lights. See if the problem follows the ballast.

 

Is there another way to check besides interchanging the ballast? Never done it