Why does my DIY power switch keep failing?

I had one I bought a while ago, it shortly after got stuck in the on position. So I bought another one, and now after installing it and testing it to working, while tucking the cables in, it did the same thing. it actually turned itself on. then stayed that way. I was careful to make sure theres no wires shorting (heatshrink and electrical tape after every solder), there was no sparks, no noise, just on, and won’t turn off.

What am I doing so wrong?

pictures please!

I just desoldered it. :frowning: I need the board ready in 30 minutes to go to class so i need to get connectors.