Electrical issues getting the truck to turn on.

I could really use some help. Yesterday I removed my battery terminals to clean some corrosion along with cleaning my air filter. The truck fired up perfectly right after, then on the second startup, I started having issues. I’ll turn the key to turn on the vehicle and all I get is a click from the starter followed by all lights in the truck going dark. If I leave the key in the same position the lights will come back on in a few seconds. The strange part is that this doesn’t happen every time, I can keep trying and it will turn on eventually, however sometimes in between trying to turn it on a check engine light for P0335 will appear followed by the 4lo light flashing and trac light on. The thing is though I can turn the key a few more random times and then the warning lights will be off. I suspected the culprit could have been a bad battery so I put a new one in and it made no difference. I then thought it could be the starter but am not confident about that because of all the electrical glitches that are happening. The terminals are clean as a whistle along with the posts on the battery. My footwell light is also flickering which it never has done since these issues started. If anyone knows anything please let me know thanks.

 

Double check battery connections and if all good then bring it to get tested. Could be the battery is going bad