I'm learning about electronic components. I believe this is the part which has broken and made this heating pad unsafe to use. Well, unusable, not just unsafe lol.
If anyone is wondering, that glass diode package is called a MELF. I don’t know why.
They suck because they roll off the PCB during the pick and place process due to low surface area contacting with the solder paste.
I’ve had to replace so many of them.