The key should shut off the light so something weird is going on. Try removing the wires to the alternator and see if the light go out. If it does, clean the alternator contacts and put the wires back and see what happens. If the light is still on then take out the alternator to have it tested.

note: don't forget to pull the positive battery terminal before pulling alternator wires.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked