have a small electrical problem

So a while back i had a lot of issues with corrosion on battery terminals, the truck wouldn't start sometimes, the 12v outlets under the AC controls didn't work, AC control lights and the lights next to the shifter didn't work for a while too. Had the battery cleaned and a protective coating put on, since then zero problems, the AC lights and shifter lights just came on one day and have worked ever since. The 12v outlets still don't work and I'm wondering what the deal is, any advice on things i should check? is this something i can fix myself or should i just bring it in to the shop?