Focus L4-2.0L (2009)
Refer to Wiring Diagram Set 92, Parking, Rear and License Lamps for schematic and connector information. See: Diagrams/Electrical
Diagrams/Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) monitors the parking lamp request input from the headlamp switch through circuit CLS34 (GY). The SJB provides a
ground for the parking lamp relay coil (integral to the SJB) when a request for the parking lamps is received. When the parking lamp relay is energized,
voltage is routed through circuit CLS30 (VT/WH) to the rear and front parking lamps, and to the Battery Junction Box (BJB) fuse 23 (3A). The BJB
fuse 23 (3A) routes voltage to the ambient lighting system through circuit CBB23 (BN/YE).
-
DTC B1578 (Lamp Park Input Circuit Short to Ground) - an on-demand DTC that may set when the SJB detects a short to ground in the parking
lamps on input circuit.
This pinpoint test is intended to diagnose the following:
-
Wiring, terminals or connectors
-
Headlamp switch
-
SJB
PINPOINT TEST P: THE PARKING, REAR OR LICENSE PLATE LAMPS ARE ON CONTINUOUSLY
-------------------------------------------------
P1 USE THE RECORDED DTCs FROM THE SJB SELF-TEST
-
Check the recorded results from the SJB self-test.
-
Was DTC B1578 recorded?
Yes
GO to P2.
No
GO to P4.
-------------------------------------------------
P2 CHECK THE HEADLAMP SWITCH
-
Ignition OFF.
-
Disconnect: Headlamp Switch C205.
-
Carry out the headlamp switch component test.
-
Is the headlamp switch OK?
Yes
GO to P3.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch See: Headlamp/Headlamp Switch/Service and Repair. CLEAR the DTCs. REPEAT the
self-test.
-------------------------------------------------
P3 CHECK CIRCUIT CLS34 (GY) FOR A SHORT TO GROUND
-
Disconnect: SJB C2280b.
-
Measure the resistance between the headlamp switch C205-3, circuit CLS34 (GY), harness side and ground.
