Test B: One Low Beam Headlamp Is Inoperative

PINPOINT TEST B: ONE LOW BEAM HEADLAMP IS INOPERATIVE

Normal Operation - Expedition
When the smart junction box (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) and CLF05 (BU/GN) to the LH and RH low beam headlamps, respectively. Ground is supplied on circuits GD120 (BK/GN) and GD123 (BK/GY) for the LH and RH headlamps, respectively.

Navigator
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) and CLF05 (BU/GN) to the LH and RH high intensity discharge (HID) relay coils, respectively. Ground for the HID relay coils is provided through circuit GD123 (BK/GY). Switched voltage for the LH and RH HID relays is provided from the battery junction box (BJB) through circuits SBB44 (GN/RD) and SBB48 (VT/RD), respectively. When the relays are energized, voltage is routed to the LH and RH headlamps through circuits CLF30 (VT/BN) and CLF31 (YE/GY), respectively. Ground is supplied on circuits GD120 (BK/GN) and GD123 (BK/GY) for the LH and RH headlamps, respectively. The ballasts within each headlamp steps up the voltage needed to illuminate the HID bulbs.







This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- HID relay
- HID bulb
- Ballast
- Headlamp assembly
- SJB

B1-B3:

B3-B5:

B5-B7:

B8-B9:

B9-B11:

B12: