Random electrical things kept dropping out, then it just started stalling. Then couldn't be jump started after a couple of goes.

I have since charged the battery and it starts fine again, on alternator the voltage is around 15.5 but is jumping around anywhere from 15 to 16. The alternator light is flashing still. alternator belt has around 10mm flex in middle.

This white block has a spring in it (which i'm guessing is a resistor) was hot and making noises coinciding with the flashing of the alternator light. But that could just be the random voltage
jumps that are going through it.



What is the diode and how do i check it?