I purchased a replacement panel from this site along with a bezel. It took a while for me to figure out how to wire it in, but was ultimately successful. See this link for my 40.5 which I would guess is similar to other models: Hunter 40.5 Owner Modifications and Upgrades
Rick,
You might want to look into something.
The original panel install had a rectifier installed. (Anode facing the panel)
This was to prevent the ship’s voltage to back feed the panel.
Your description of feeding voltage from the dc panel and picking up polarity at the solar panel implies that this diode is shorted or missing.
A 1N5401 will do the job. I believe the solar panel ties in at the battery switch
Good luck
