A couple of weeks ago, I upgraded the battery to the 51R. I also did some minor maintenance - Seafoam in the gas tank, changed the air filter, cleaned the MAF sensor. Minor things.

Yesterday, my car alarm started to go off. I turned it off. It came back on. The second time, I went outside because the lights stayed on after turning it off. I could hear these noises. I’m not sure what it going on.

I disconnected the battery in fear of an electrical fire.

Any ideas?
Link to a video I posted to Reddit
https://www.reddit.com/r/hondafit/co...trical_noises/

 

First thing I'd do is see if your ECM generated any DTC (error) codes. I'm wondering if you got an improper ground in there somewhere while doing your battery swap.

If you don't have an OBD-II scanner or smartphone app, many auto parts stores will read your codes for free.