I recently replaced the alternator on my 96 Blazer Vortec V6. Tried to start it up and am getting no power to dash, headlights, pretty much anything interior. I took the battery up to the nearest parts store and replaced with a new one. Still nothing, battery reads 12.3v. Hotwired to try and start engine but it wouldn't turn over. Checked all grounds and troubleshooted power solutions but all checked out.