Test B: One Low Beam Headlamp Is Inoperative

PINPOINT TEST B: ONE LOW BEAM HEADLAMP IS INOPERATIVE

Normal Operation
The smart junction box (SJB) receives voltage from the battery junction box (BJB) through circuits SBB34 (YE/RD) (LH headlamp) and SBB29 (GY/RD) (RH headlamp). When the SJB detects the headlamp switch in the HEADLAMPS ON position and the multifunction switch in the LOW BEAM position, the SJB provides voltage through circuits CLF04 (BN/BU) (LH headlamp) and CLF05 (BU/GN) (RH headlamp) to the low beam headlamps. Ground is supplied on circuits GD120 (BK/GN) (LH headlamp) and GD123 (BK/GY) (RH headlamp).

- DTC B1797 (Lamp Headlamp Low-Beam Circuit Short to Ground) - is a continuous and on-demand DTC that sets when the SJB detects a short to ground (high amperage draw) from the LH or RH low beam voltage supply circuit. The self-test must be run after the repair in order for the SJB to enable the output for the low beam voltage supply.
- DTC B2501 (LF Lamp Low Beam Circuit Failure) - is a continuous and on-demand DTC that sets when the SJB detects an open from the LH low beam voltage supply circuit.
- DTC B2503 (RF Lamp Low Beam Circuit Failure) - is a continuous and on-demand DTC that sets when the SJB detects an open from the RH low beam voltage supply circuit.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- SJB

B1-B3:

B3-B5:

B5-B6:

B6-B7: