I am looking for a physical wiring schematic for a GP38 with static excitation. This is not a 'Dash 2' locomotive. Built 7/69. Thanks!

There is an aftermarket company called RPI. They are the official distribution outlet for all EMD documentation, including wiring schematics. Be sure to request the associated wire running list.

You will need the order number, which is stamped on the top portion of the coupler carrier.