Guys, I need help with a puzzle. Just installed new engine(3 months ago)at the Mazda dealer. last week my ingnition key fuse shorted while backing up from a parking space. entire dash lost power. checked all fuses, all good except ignition key. replaced it several times each time was blown when I put it in reverse, but not forward(manual 6). To drive home I had to replace it with 30A(mistake). I was going to go to the shop but... a week later while driving I saw smoke coming out from under the hood and could smell plastic. after i pushed clutch I heard some grinding which I thought was a clutch. It was not. it was starter engaging. I stopped. after checking I found that in accesory key position i dont have to turn my ignition key to start the car.
when the key was/is in on position to start the car just press the clutch so safety switch is released. any idea what could cause it. Just paid 5k for a new engine. warranty is gone(150k).

there was no other work done on the car since an engine was replaced. Help