My guess is near the battery box on the inside of your trailer. Check your user manual for the location of the solar pre-wiring. The controller is located at the location where the manual specifies the pre-wiring terminates in the interior of the trailer.
__________________
Al, K6IV
2015 30' Classic, "Chez Nu"
2014 RAM 2500 w/Cummins Diesel
ProPride Hitch, 400 W Solar
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.