Hopefully our side discussion stayed relevant enough.
Whether the stereo draw could have added to the load on that connector depends on whether it was added to the switched side of the fuse box or the always side of the fuse box. That's what Redfish was getting at. How much it added is another question. If its not turned up to 11 on a big amp its prob not a big load.
I'd check the condition (post 11) and if OK, reassemble and do some voltage drop checks.
