The fuse in the fuse box will have blown,remove the fuse then remove the cover on the pullcord switch,you may find blackened terminals or loose wires,tighten all connections to the wires,these are heavy duty switches and take a lot of stick, a poor connection causes heat buildup and falure,causing blown fuses,replace cover and renew fuse then try it,if it blows again call in a sparky.
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