On Saturday, September 7, 2019 at 8:36:30 AM UTC-7, Chuck Lohre wrote:
Hi All,

Trying to figure out what is wrong with my system and would like a harness to test the radio, Dittle speaker box, and Dittel mic, push to talk outside the glider. Please email me chuck at lohre dot com or call 513-260-9025. Thanks.

I'm guessing you are looking for used and sure you already know, but Cumulus sells the wiring harness for $130 and the speaker box for $155.

https://www.cumulus-soaring.com/dittel.htm#F10028