Whats wrong with my open and close door script?

Maybe you can try another script, simpler and short, and easier to learn.

I will declare the debounce value, that's @CeramicTile said.

Before this, you must make the "Part" and "Door"s' parent to Workspace, or the script won't work if those are not parented by Workspace.

Anyways, let insert debounce inside.

debounce = false

By the way, I think your script is way too messy. Let make shorter, don't need to use a function, let just fire the code while 'Part' got stepped.

debounce = false

game.Workspace.Part.Touched:Connect(function(plr)

end)

P.S. 1, When your code contained :Connect(function(), remember to place the 'end' become 'end)'.

P.S. 2, I'll say again, the last of the line doesn't need to contain script.Parent.Touched:Connect(onTouched). Don't add yourself!

Ok, anyways, let continue our script, when Part got stepped, the door will change the properties.

debounce = false

game.Workspace.Part.Touched:Connect(function(plr)
    debouce = true 
    game.Workspace.Door.Transparency = 1
    game.Workspace.Door.CanCollide = false
    wait(5)
    game.Workspace.Door.Transparency = 0
    game.Workspace.Door.CanCollide = false
    debouce = false
end)

Tada! A working script. Simple as you think! winks

Bye! Have a good day in Roblox Studio, I hope you like ROBLOX! :D

I would propose you add in a debounce variable so the touch event doesn't fire multiple times during the 5 second interval that the door it already open.

local debounce = true --//Declaring the debounce variable

local function onTouched(otherPart)
    if (not debounce) then return end --//We are returning nil which will make sure that all the code below will not be executed because debounce is false

    local character = otherPart.Parent
    if character then
        local player = game.Players:GetPlayerFromCharacter(character)  
        if player then
            debounce = false --//Setting it to false so the touch function doesn't fire more than once during this 5 second interval

            game.Workspace.Part.Door.CanCollide = false
            game.Workspace.Part.Door.Transparency = 1
            wait(5)
            game.Workspace.Part.Door.CanCollide = true
            game.Workspace.Part.Door.Transparency = 0

            debounce = true --//This will allow the code above to get run again
            --return onTouched --//We don't need to return anything at this point 
        end
    end
end

script.Parent.Touched:Connect(onTouched)

Otherwise everything else seems fine, hope it works.