The vehicle was parked outside overnight at West Side Honda, Knoxville's WBIR-TV reported. Workers there say the reptile may have slithered off on its own during the night.
The driver was on Interstate 40 in Knoxville late Tuesday when he was startled to discover he had an unwelcome passenger. He called for help, and state troopers said they could see the snake inside the dashboard but could not reach it.
The car was towed to West Side Honda so the dashboard could be removed.
"Six years on the highway patrol, this is the first one. But as a sheriff's deputy, I dealt with this quite a bit, but yes this is the first snake call in a vehicle I've answered as a trooper," said John Carr of the Tennessee Highway Patrol.