Vintage Parts Repair Mini Tyco Mutator RC Car 27MHz

Car is about 8" long. The car starts driving forward on its own when both it and the remote are turned on. It does not move very fast. One battery contact on the car has a little rust/corrosion. The remote is missing its cover, but the battery compartment is clean. The car does not respond when the trigger is pulled on the remote, but as mentioned, the motor engages when both parts are turned on.