Rear tail lights wont come one when i turn my lights on. all lights work except these. i dont have an owners manual because this vehicle is salvaged with minor front damage, although the airbags did not deploy. i dont have the owners manual to check if i have all the fuses, but with the ones i do have none are blown. i have checked the relays and they seem to work although im not exactly sure. i have no clue which one would operate the rear lights. ive been told it could be 1 of 4 things.. head light switch, relay, fuse, or pinched wires. any help would be great. thanks
Do you know what a smart junction box is ? This fords BCM - body control module .( computer )
The smart junction box (SJB) monitors the headlamp switch position by sending multiple voltage reference signals to the headlamp switch. When the headlamp switch is in any given position, that input signal is routed to ground.
When the SJB receives an input from the headlamp switch indicating a request for the parking lamps, the SJB energizes the parking lamp relay, which supplies voltage to the exterior lamps.
Visual Inspection Chart
Mechanical
Electrical
NOTE: Make sure the headlamp switch is in the OFF position.
NOTE: Make sure the multifunction switch is in the LOW BEAM position.
Smart Junction Box (SJB) Diagnostic Trouble Code (DTC) Index
DTC
Description
Source
Action
B1342
ECU is Faulted
SJB
CLEAR the DTCs. RETRIEVE the DTCs. If DTC B1342 is retrieved again, INSTALL a new SJB. REFER to Section 419-10 .
B1578
Lamp Park Input Circuit Short to Ground
SJB
Go To Pinpoint Test R .
Symptom Chart
Symptom Chart
Condition
Possible Sources
Action
Do you know how to do automotive electrical circuit testing ?
Pinpoint Test Q: One Or More Parking, Rear or License Plate Lamps Is Inoperative
Normal Operation
Voltage is supplied to the smart junction box (SJB) from the battery junction box (BJB) fuse 23 (60A) through circuit SBB23 (WH/RD).
When the headlamp switch is placed in the PARKING LAMPS ON position, the SJB provides a ground for the parking lamp relay coil (internal to the SJB). When the parking lamp relay is energized, voltage is sent through circuit CBP08 (GY/YE) to the rear and front parking lamps. Ground is provided to the rear parking and license plate lamps through circuit GD171 (BK/GY). Ground is provided to the front parking and side marker lamps through circuits GD121 (BK/GY), GD121 (BK/RD), GD121 (BK/YE), GD121 (GY/YE), GD123 (BK/YE) or GD123 (BK/GY).
Possible Causes
SOURCE: Ford Focus seatbelt locked
There is a gas cylinder that tightens the belt in a minor collision, it is a one time use part it is independent of the air bag deployment system, you will have to replace the seat belt gas cylinder, that may mean a new belt assembly, not sure on focus.
SOURCE: airbag light is on. Minor front end impact no deployment. reset?
sounds like the sensor or the sensor connection is damaged have a look see. the connection might just be loose or disconnected. if this helps please rate me
SOURCE: my blower motor stopped working, front and back of van.
My rear blower motor stopped working and my Brother took the unit apart. He found out that the fan blade had seized up the unit. After he took out blade and sanded down blades, it worked fine. However, I am not sure about your front unit. Good luck.
SOURCE: 2004 F150 Tail light problem
I would check your Auxiliary relay box. Check the R03 relay you might need to replace it. The Auxiliary relay box is located in the engine compartment (driver side)
276 views
Usually answered in minutes!
×