Hey everyone I've got a few door sensors but i've got one that stopped working. This isn't a surprise since this house has had slightly over 50% fail rate for those units replaced(Side note: switching to lithium batteries might be fixing them frying them at low volts, can't complain too much as SmartHome has been great so far). I have a new failure type not the typical unit doesn't power up or anything. This one if you press the  button the LED does indeed light up but doesn't light up when you pass the magnet by the sensor even touching it to the unit. I would assume the magnet probably isn't bad but the sensor that reads the field might be? Is there much to test, the board looks pretty clean.

If the magnetic switch is not closing. You maybe able to use a test clip lead and jump across the switches lead wires. If the LED lights then the switch maybe not closing.  I don't know how it would act if the switch was stuck closed. You could try tapping it a few times and see if it works.

Smarthome replaced it so I didn't end up tinkering around with it. But the connections for the sensor didn't have any cracks in the solder.

The magnetic switch probably failed and was not closing when it should of.