If it does not earth correctly, then it won't work correctly. If your indicators are dim, then this new earth cable might be all they need to restore there full brightness; a dim indicator can be dangerous, so make sure yours are performing as they should. It is always worth while to check all your earth wires, and make sure they are up to the job. All are stocked at CMS, so if yours is brittle and with cracked insulation, than check out the online 'parts list' fiche for your model, and brighten up your lighting system.
Suited for models: