Rear right Blinker out fuse and bulb are good
Is it just the back turn signal that's not working or is it the front too? If it's both your turn signal switch in the steering column has probably gone bad. If it's just the rear you probably have a short or a bad ground. Needs to go to an electrical shop. If it's the kind I'm thinking of it has its own circuit board in the taillight. Those tend to corrode and go bad.
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