I updated the wire diagrams based on new information. I added a fan output and configuration module to the GTN-650. The new link is:
Garmin can be a little frustrating in relation to connectors for their avionics. Some come with the component, some are purchased separately as install kits, some are not available at all to the experimental installations. If they are reading this, it would be a good thing to simplify for us builders. Specifically the GTN-650 has no connector kit available, at least through Aircraft Spruce. They sell it only with a pre-fabricated harness. And, if you don't want a pre-fab harness ... well .... Stein to the rescue!
Stein set me up with the install kit from a GTN-650. It includes 4 connectors, a rack mount, a config module and the back plate/fan. Other than a handling fee, I will get a credit from Stein when I purchase the GTN-650.
The GTN-650 is now fully installed.
Thank you to Stein.