Why does this script not index "veh"?

veh = game.Workspace:FindFirstChild(script.Parent.Parent.CarName.Value, true)
airhorn = veh.lightbar1.middle.Manual
function Click(mouse)
airhorn:Play()
veh.lightbar1.middle.Yelp:Stop()
veh.lightbar1.middle.Wail:Stop()
end
function Unclick(mouse)
airhorn:Stop()
end
script.Parent.MouseButton1Down:connect(Click)
script.Parent.MouseButton1Up:connect(Unclick)

I get error cannot index veh. I have a script giving the cars a unique random name and the CarName value matches it (I checked and that works).