I emailed airstream yesterday for a wiring diagram for my '99 28' and I received one today (pdf). Maybe it depends on who looks at your email. BTW I sent my request to customer service. I explained why I wanted it etc. I had a diagram for a 25' (which is likely pretty similar) but I wanted to get the '99 if I could. I must say that I appreciate them sending it to me.
1999 28' Safari
2012 F150 Platinum Max Tow 7650 GVWR 3.73 Elec. Locking Diff.(Prev 2003 Dmax).
Honda EU2000i, Equalizer Hitch
AM Solar Panels 150W - 2 Trojan T 105 6V Batteries
On internet forums, please research and separate the wheat from the chaff (including mine!)