I'm not sure what you mean by rotor and collector.

The warning light needs to come on when you turn the ignition to run. If it does not, then the alternator will not work when the engine starts. Suggest that you check the bulb and the blue wire running to it from the alternator.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe