Hey guys. I made a huge mistake while it was dark outside and put my battery in backwards.. I realized as soon as I connected it hurried and switched it around and now I've been having all sorts of problems...

So I replaced my alternator when my new battery died on me while driving to work , from they're I had to get it taken into my mechanic my BAS ESP light comes on once I start driving and the engine temperature gauge was almost red lining... Also my stereo won't turn on anymore..
Anyone have an idea of what I could potentially look at or help my mechanic find? Any help would be greatly appreciated!