http://www.nostalgiaair.org/PagesByModel/495/M0022495.pdf I am going to pick up the IFR service monitor Monday. If I remember right it will almost generate a signal from dirt to white light.
I just pulled up the Chevy schematic there are some subtle differences but the same basic stuff. The Chevy manual is much more detailed and has a lot more trouble shooting information. It pretty much looks like electronics for mechanics step by step. It even has pictures of where to hook up the signal generator. This should make things easier. The section on installation is great. I should have printed it off long ago.