Whichever one illiminates the turn signal. Would also be a brake light, i think explorers do that. So just turn all lights on and see whats missing

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1995 f-150 4x4 4.9 inline 6 5-speed
1996 Ranger 3.0 2wd Auto 4r44
2008 Ranger 4.0 4x4 Auto 5r55 extended cab