ANN ARBOR, Mich.—Tesla Motors Inc. is fighting legislation in Michigan that would prevent the electric-car maker from direct selling or servicing its vehicles in the state, the latest in a long line of battles the company has faced related to its distribution model.

The Silicon Valley-based auto maker has gone against industry standards, looking to sell direct to customers rather than use franchises. In most states, franchise laws protect dealers from manufacturers setting up company-owned retail networks.

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