Service Manual Isn't on MyMopar

I am trying to fix the wiring in my 76 Plymouth Duster. Some people have recommended downloading the service manual from Mymopar.com, but the service manual for Plymouth Valiant stops at 72. Does anyone know where I can find the manual online? The wiring is apparently different from previous years, so I would like to find one specifically for 1976. I wouldn't mind buying one if they sell one for a 76 Duster. Thanks.