? Unhook 80s Lionel diesel horn kit?

[Boyd]

I have an 1981 GP9 (GP38 as the box said) #8158 DMIR engine. The horn kit I got (Lionel brand) from I think Train World and wired it as the kits instructions said to. Well it has always sounded terrible and I can't run the engine off of DC this way and want to completely remove the diesel horn kit. Anyone know of detailed instructions to get the wiring back to stock. Boyd.