wiring diagram for emersom window airconditioner Mod 18ht42

Given that this is a single unit window air conditioner with the power cord attached, which wiring diagram are you looking for? Installation wiring diagram should be very easy since you have the cord or at least the three clearly labeled screw terminals for live, neutral and ground conductors.

Internal wiring diagram would be impossible to obtain for this early 90s model. You may have to approach it  as any other electric/electronics device with the schematics missing: open it up and trace the internal wiring using a multimeter in resistance mode.

What exactly are you trying to do with the unit? Are you repairing one? What is wrong with it, maybe there are things you can do without the complete wiring digram?