Try on-board diagnostics first with a OBD2 terminal attached. Search for the specific code. The needle should not die like this. Its flickering for a reason.
F-CAN or B-CAN are down and/or limping. Debug them first:
Push and hold the SEL/Reset
Turn headlights ON
Turn ignition switch to II
Within 5 seconds, turn headlights OFF, then ON, then OFF again
Within 5 seconds, release SEL/Reset then push three times.
You can exit this by turning the ignition off.
Invest in a factory service manual.