i cant turn steerhinge. whats wrong?

local car = seat.Parent
local leftDrive = car.Body.LeftDrive
local rightDrive = car.Body.RightDrive
local steerHinge = car.FrontAxle.SteerHinge
local steeringAngle = 30
local maxSpeed = 20

local function onChanged(property)
	if property == "Steer" then
		steerHinge.TargetAngle = steeringAngle * seat.Steer
	end
	if property == "Throttle" then
		leftDrive.AngularVelocity = -maxSpeed * seat.Throttle
		rightDrive.AngularVelocity = maxSpeed * seat.Throttle
	end
end

seat.Changed:connect(onChanged)

i cant turn steerhinge whats wrong with my script?