The southbound lanes closed between exit 37 to Route 233 in Newville, and exit 29 to King Street in Shippensburg around 1 p.m., according to traffic maps on 511pa.
Traffic in the area was bumper-to-bumper in because of the sudden closure.
No injuries have been reported according to dispatch.
The highway will remain closed until crews knock down the fire and have the vehicle towed from the scene, say Emergency Dispatch Services.
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