Hello! Without having the vehicle to actually run tests it is imposable to say for sure. But, (and I am assuming here that you have checked and are sure that the turn signals, fan motor, and reverse lights all work with a new fuse before putting the vehicle into park, and continue to work until you shift into park). I would start by looking in the steering column, it sounds like there may be a wire pinched when moving the lever up into the park position. My guess would be a turn signal switch wire. But this is just a place to start.
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