Try this...from the VAC Site
Q: I need an owners and service manual for my Airstream. Where can I get one?
A: The first owners manuals were published in 1964. Prior to that, the owner received a brown envelope containing parts lists and other helpful information on the accessories in his trailer. The VAC has started making these available in the Members Archive section. A service manual with instructions for performing service operations did not exist until 1972.
You can get photocopies of owners manual (1964+) and service manuals (1972-1986) from:
Helen Davis Secretarial Services
PO Box 484 Sidney, OH 45365
Prices are about $33 and $70 respectively. After 1986 the Owners Manuals included available service information.
This would probably have the wiring diagram you are looking for. If you think a '64 GlobeTrotter one would help, PM me and & can email a copy of mine to you...Good Luck!