Hello. Trying to troubleshoot and hopefully fix a Kenmore Upright freezer I've owned a little less than 3 years. It lives in my garage and it's been very hot (100-110F) here lately.

Caught it last week at 35F and noticed the interior light wasn't on. Thought maybe a sealing issue to cleared some stuff out of the way and closed the door tight. Over the next couple days it got back down to 0F. Yesterday found it at 35F again, again no light on. I can hear a compressor hum, but it's not too loud and it doesn't kick on hard when i have the door open or anything.

I started moving things out of there today. Left the door open for a bit. Somewhere during that time frame the interior light came on and I could hear more noise from the unit. Like I would expect from a compressor desperately trying to cool. Left a few unimportant things in the freezer this afternoon Noticed it's already back down to 15F (lights still on).

I'm thinking it's too coincidental when light = on, unit=working and vice versa. Because it's showing it CAN cool when it wants too, I'm thinking it's not the compressor but more of a control board somewhere.

Ideas where to start. I don't have a huge amount of time to troubleshoot this thing. I have plenty of tools but if this is something that could still lead to bad results I might call someone out instead or replace.
THanks for the help!
Pete