B420 Hi/LO Beam Relays Circuit

Hi/Low Beam Circuit Problem:

Schematic:

DESCRIPTION
If the HI/LO beams did not cycle on and off when B006 was selected, then this is the system that set Code B420.

TEST DESCRIPTION
The numbers below refer to circled numbers on the diagnostic chart:
1. Checks to see if the fault is due to an open circuit or a short to ground in the circuit. If the HI beams are always on, then there is a short to ground in control circuit and if the HI beams never turn on, then there is an open in one of the circuits.
2. Checks to see if the short to ground is due to the circuit or the Body Control Module (BCM).
3. Check to see if the open circuit is due to the circuit or the BCM.
4. Check to see if the open circuit is on the power or ground side of the relay.

NOTE ON INTERMITTENTS
If an intermittent Code B420 is being set manipulate the related wiring in output function and watch for relays to cycle.