P3690152AB Wiring Harness Kit ground wire short

I'll repeat. The thing that MUST be grounded is the BOX. In all OEM installations, the WAY they are grounded is mounted tight to the firewall. This is poor practice, but people did "get away" with it. Forty years later, with rust, corrosion, and stripped bolt holes, not so much.

As long as the box flanges are scraped clean, and the firewall likewise, mount the box with star lock washers. The bolts must be tight.........not stripped out.

Frankly, I'm tired of this dance. You refuse to give details, I've no idea what you are about here