Car-Trailer 7way connector 70 Int.27'
Greetings capt ken!
It sounds as if your Airstream may still be wired to the 1970 unique to Airstream pattern. What you describe is typical when an Airstream with connector wired to that pattern is connected to a modern tow vehicle with current industry standard RV towing connector. You can check your Airstream's owner's manual for the OEM wiring pattern as well as color/function description for the wiring (also different from current standards). It is a fairly easy job to rewire the trailer's plug to match today's industry standard configuration.
If the Airstream has functioned properly with this tow vehicle in the past, I would highly suspect the possibility of dirt and/or corrosion bridging between terminals in the connector. I had frequent problems with corrosion in the blade style connectors that ended when I made the switch to heavy duty round-pin connectors similar to those utilized in the trucking industry.
Good luck with solving your connector issue.
Kevin D. Allen
WBCCI (Lifetime Member)/VAC/Free Wheelers #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 VORTEC/4.11 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 Liter V8/2.70 Final Drive)