It's a basic bridge rectifier and dropping resistor arrangement. D2-D4 are the bridge rectifier, so input polarity does not matter. D1 might be a TVS surge protector.
R1, R2 and R3 (not populated) are series current-limiting resistors.
So the halo could see 14V- the LEDs drop - (2*0.7V)/(43R+62R) for current. Assuming white LED's, that are 3.2V each, that's only 11mA- not too much really unless my math is wrong.
To troubleshoot, it's most likely LED's. Heat can make them flicker and go open circuit, so look for any one LED going open-circuit in the string.
If you are getting a ground-fault where one end of the LED halo shorts to chassis ground, hard to make happen.