Interior Lighting System: Overview Ford Ranger II

The interior lighting system consists of the following

1. Dome lamp
2. Instrument panel dimmer switch
3. Door ajar switch (located on both the front and rear door latches)
4. Smart junction box (SJB)

Special Tools Illustration Tool Name Tool Number Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool 73III Automotive Meter 105-R0057 or equivalent

Scheme 1

When the smart junction box (SJB) detects a request for lighting, it turns on the interior lamp by supplying power to the lamp. The request for lighting can be a signal from a door ajar switch, an interior lighting on command from the instrument panel dimmer switch or an unlock command from a remote keyless entry (RKE) transmitter. The door ajar switches are hard-wired directly to the SJB. The door ajar switches are normally open when the doors are closed. All door ajar switches receive voltage from the SJB and each has its own ground circuit. The instrument panel dimmer switch receives voltage from the SJB and has its own ground circuit. The instrument panel dimmer switch provides variable resistance for backlight the instrument cluster and a toggle on/off function for the courtesy lamp.

The inputs are

1. Ignition switch position
2. LH front door ajar switch
3. RH front door ajar switch
4. LH rear door ajar switch
5. RH rear door ajar switch
6. RKE unlock signal

For additional door ajar switch information, refer to HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS .

The output is

1. Interior lamp relay

Normal Operation

Voltage is supplied to the smart junction box (SJB) through circuit SBB05 (GY/RD). The SJB fuse 13 (15A) supplies voltage to the interior lamp relay (integral to the SJB). When any door is opened, the door ajar switch closes, signalling the SJB. The SJB monitors the door ajar circuits, and the instrument panel dimmer switch input. Based on these inputs, the SJB will supply voltage to the interior lamp on circuit CLN28 (GN/BU).

Possible Causes

1. Fuse
2. Circuit CLN28 (GN/BU) open or short to ground
3. Interior lamp
4. SJB

Scheme 2

Scheme 3

Scheme 4

1. A1 CHECK CIRCUIT CLN28 (GN/BU) FOR VOLTAGE Key in ON position. Disconnect: Front Dome Lamp C931 Measure the voltage between the interior lamp C931-1, circuit CLN28 (GN/BU), harness side and ground. Is the voltage greater than 10 volts? YES : INSTALL a new interior lamp. TEST the system for normal operation. NO : VERIFY the SJB fuse 13 (15A) is OK. If OK, go to A2 .
2. A2 CHECK CIRCUIT CLN28 (GN/BU) FOR AN OPEN Key in OFF position. Disconnect: SJB C2280c Measure the resistance between the SJB C2280c-8, circuit CLN28 (GN/BU), harness side and the front dome lamp C931-1, circuit CLN28 (GN/BU), harness side. Is the resistance less than 5 ohms? YES : Go to A3 . NO : REPAIR the circuit. TEST the system for normal operation.
3. A3 CHECK CIRCUIT CLN28 (GN/BU) FOR A SHORT TO GROUND Measure the resistance between the SJB C2280c-8, circuit CLN28 (GN/BU), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to A4 . NO : REPAIR the circuit. TEST the system for normal operation.
4. A4 CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: corrosion pushed-out pins Connect all the SJB connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new SJB. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-268767) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.

Smart junction box (SJB) fuse 13 (15A) supplies voltage to the interior lamp relay (integral to the SJB). When any door is opened, the door ajar switch closes, signalling the SJB. The SJB monitors the door ajar circuits, and the instrument panel dimmer switch input. Based on these inputs, the SJB will supply voltage to the interior lamp on circuit CLN28 (GN/BU).

Possible Causes

1. Circuit CPL12 (VT/OG) short to ground
2. Circuit CPL26 (GN/VT) short to ground
3. Circuit CLN27 (WH/BN) short to ground
4. Circuit CLN28 (GN/BU) short to voltage
5. Circuit CPL31 (WH) short to ground
6. Circuit CPL36 (GN) short to ground
7. Circuit CPL39 (YE) short to ground
8. Instrument panel dimmer switch
9. Four-wheel drive (4WD) control module
10. Instrument cluster
11. Door ajar switch
12. SJB

Scheme 5

Scheme 6

Scheme 7

1. B1 CHECK THE DOOR AJAR PID STATUS WITH THE SCAN TOOL Key in ON position. Close all the doors. Enter the following diagnostic mode on the diagnostic tool: SJB Door Ajar PIDs Monitor the door ajar PIDs. Do the door ajar PIDs match the door positions? YES : Go to B2 . NO : If the LH front door PID does not match the door position, go to B5 . If the RH front door PID does not match the door position, go to B10 . If the LH rear door PID (if equipped) does not match the door position, go to B12 . If the RH rear door PID (if equipped) does not match the door position, go to B14 .
2. B2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH Key in OFF position. Disconnect: Instrument Panel Dimmer Switch C206 Is the interior lamp still illuminated? YES : Go to B3 . NO : INSTALL a new instrument panel dimmer switch. REFER to «INSTRUMENT CLUSTER AND PANEL ILLUMINATION»(ref-268796) . TEST the system for normal operation.
3. B3 CHECK CIRCUIT CLN27 (WH/BN) FOR A SHORT TO GROUND Disconnect: SJB C2280d Measure the resistance between the SJB C2280d-10, circuit CLN27 (WH/BN), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B4 . NO : REPAIR the circuit. TEST the system for normal operation.
4. B4 CHECK CIRCUIT CLN28 (GN/BU) FOR A SHORT TO VOLTAGE Disconnect: SJB C2280c Is the interior lamp still illuminated? YES : REPAIR the circuit. TEST the system for normal operation. NO : Go to B16 .
5. B5 CHECK THE LH FRONT DOOR AJAR SWITCH FOR A SHORT TO GROUND Disconnect: LH Front Door Ajar Switch C526 Enter the following diagnostic mode on the diagnostic tool: SJB Door Ajar PID Monitor the door ajar PID. Did the door ajar PID change with the switch disconnected? YES : INSTALL a new door ajar switch. REFER to «HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS»(ref-268772) . TEST the system for normal operation. NO : Go to B6 .
6. B6 CHECK CIRCUIT CPL26 (GN/VT) FOR A SHORT TO GROUND Key in OFF position. Disconnect: SJB C2280c Measure the resistance between the LH front door ajar switch C526-1, circuit CPL26 (GN/VT), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B7 . NO : REPAIR the circuit. TEST the system for normal operation.
7. B7 CHECK CIRCUIT CPL12 (VT/OG) FOR A SHORT TO GROUND Measure the resistance between the SJB C2280c-2, circuit CPL12 (VT/OG), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B16 . NO : Go to B8 .
8. B8 CHECK THE INSTRUMENT CLUSTER Disconnect: Instrument Cluster C220a Measure the resistance between the SJB C2280c-2, circuit CPL12 (VT/OG), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B17 . NO : Go to B9 .
9. B9 CHECK THE 4WD CONTROL MODULE Disconnect: 4WD Control Module C281a Measure the resistance between the SJB C2280c-2, circuit CPL12 (VT/OG), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B18 . NO : REPAIR the circuit. TEST the system for normal operation.
10. B10 CHECK THE RH FRONT DOOR AJAR SWITCH FOR A SHORT TO GROUND Disconnect: RH Front Door Ajar Switch C602 Enter the following diagnostic mode on the diagnostic tool: SJB Door Ajar PID Monitor the door ajar PID. Did the door ajar PID change with the switch disconnected? YES : INSTALL a new door ajar switch. REFER to «HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS»(ref-268772) . TEST the system for normal operation. NO : Go to B11 .
11. B11 CHECK CIRCUIT CPL31 (WH) FOR A SHORT TO GROUND Key in OFF position. Disconnect: SJB C2280d Measure the resistance between the RH front door ajar switch C602-1, circuit CPL31 (WH), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B16 . NO : REPAIR the circuit. TEST the system for normal operation.
12. B12 CHECK THE LH REAR DOOR AJAR SWITCH FOR A SHORT TO GROUND (IF EQUIPPED) Disconnect: LH Rear Door Ajar Switch C715 Enter the following diagnostic mode on the diagnostic tool: SJB Door Ajar PID Monitor the door ajar PID. Did the door ajar PID change with the switch disconnected? YES : INSTALL a new door ajar switch. REFER to «HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS»(ref-268772) . TEST the system for normal operation. NO : Go to B13 .
13. B13 CHECK CIRCUIT CPL36 (GN) FOR A SHORT TO GROUND Key in OFF position. Disconnect: SJB C2280d Measure the resistance between the RH rear door ajar switch C715-1, circuit CPL36 (GN), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B16 . NO : REPAIR the circuit. TEST the system for normal operation.
14. B14 CHECK THE RH REAR DOOR AJAR SWITCH FOR A SHORT TO GROUND (IF EQUIPPED) Disconnect: RH Rear Door Ajar Switch C820 Enter the following diagnostic mode on the diagnostic tool: SJB Door Ajar PID Monitor the door ajar PID. Did the door ajar PID change with the switch disconnected? YES : INSTALL a new door ajar switch. REFER to «HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS»(ref-268772) . TEST the system for normal operation. NO : Go to B15 .
15. B15 CHECK CIRCUIT CPL39 (YE) FOR A SHORT TO GROUND Key in OFF position. Disconnect: SJB C2280d Measure the resistance between the LH rear door ajar switch C820-1, circuit CPL39 (YE), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B16 . NO : REPAIR the circuit. TEST the system for normal operation.
16. B16 CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: corrosion pushed-out pins Connect all the SJB connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new SJB. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-268767) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
17. B17 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all the instrument cluster connectors. Check for: corrosion pushed-out pins Connect all the instrument cluster connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new instrument cluster. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-268767) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
18. B18 CHECK FOR CORRECT 4WD CONTROL MODULE OPERATION Disconnect all the 4WD control module connectors. Check for: corrosion pushed-out pins Connect all the 4WD control module connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new 4WD control module. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-268767) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

When any door is opened, the door ajar switch closes and signals the smart junction box (SJB). The SJB receives the door open signal and activates the interior lamp relay (integral to the SJB) and applies voltage to circuit CLN28 (GN/BU).

Possible Causes

1. Circuit CPL26 (GN/VT) open
2. Circuit CPL31 (WH) open
3. Circuit CPL36 (GN) open
4. Circuit CPL39 (YE) open
5. Circuit GD161 (BK/YE) open
6. Circuit GD175 (BK/BU) open
7. Door ajar switch
8. SJB

Scheme 8

Scheme 9

1. C1 CHECK THE DOOR AJAR PIDs Key in ON position. Enter the following diagnostic mode on the diagnostic tool: SJB Door Ajar PIDs Monitor the door ajar PIDs while opening and closing the doors. Do the PID values agree with all the door positions? YES : Go to C5 . NO : Go to C2 .
2. C2 CHECK GROUND CIRCUIT FOR AN OPEN Key in OFF position. Disconnect: Suspect Door Ajar Switch Measure the resistance between the suspect door ajar switch, harness side and ground as follows: Location Connector-Pin Circuit LH front C526-2 GD175 (BK/BU) RH front C602-2 GD161 (BK/YE) LH rear C715-2 GD161 (BK/YE) RH rear C820-2 GD161 (BK/YE) Is the resistance less than 5 ohms? YES : Go to C3 . NO : REPAIR the circuit. TEST the system for normal operation.
3. C3 CHECK THE DOOR AJAR SIGNAL CIRCUIT FOR AN OPEN Disconnect: SJB C2280c (LH Front) or C2280d (All Other Doors) Measure the resistance between the inoperative door ajar switch and the SJB as follows: Location Door Ajar Connector-Pin SJB Connector-Pin Circuit LH front C526-1 C2280c-6 CPL26 (GN/VT) RH front C602-1 C2280d-3 CPL31 (WH) LH rear C715-1 C2280d-4 CPL36 (GN) RH rear C820-1 C2280d-6 CPL39 (YE) Is the resistance less than 5 ohms? YES : Go to C4 . NO : REPAIR the circuit in question. TEST the system for normal operation.
4. C4 CHECK THE DOOR AJAR SWITCH Measure the resistance between the suspect door ajar switch pin 1, component side and the suspect door ajar switch pin 2, component side while toggling the switch open and closed. Is the resistance less than 5 ohms when the switch is released and greater than 10,000 ohms when the switch is pressed? YES : Go to C5 . NO : INSTALL a new door ajar switch. REFER to «HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS»(ref-268772) . TEST the system for normal operation.
5. C5 CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: corrosion pushed-out pins Connect all the SJB connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new SJB. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-268767) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

The illuminated entry provides interior lighting whenever the smart junction box (SJB) receives an UNLOCK request from the RKE transmitter. The SJB receives the RKE signal and activates the interior lamp relay (integral to the SJB) and applies voltage to circuit CLN28 (GN/BU).

Possible Causes

1. RKE system
2. SJB

The instrument panel dimmer switch controls the demand lighting function. When the instrument panel dimmer switch is closed, the voltage reference circuit signals the smart junction box (SJB). The SJB monitors the instrument panel dimmer circuit, and based on the status, the SJB will supply voltage to the interior lamp on circuit CLN28 (GN/BU). Circuit CLN28 (GN/BU) then supplies voltage to the interior lamp. The interior lamp relay in the SJB deactivates the voltage after a predetermined time-out.

Possible Causes

1. Circuit CLN27 (WH/BN) open
2. Circuit GD161 (BK/YE) open
3. Instrument panel dimmer switch
4. SJB

Scheme 10

Scheme 11

Scheme 12

Scheme 13

1. E1 CHECK CIRCUIT CLN27 (WH/BN) FOR VOLTAGE Key in OFF position. Disconnect: Instrument Panel Dimmer Switch C206 Key in ON position. Measure the voltage between the dimmer control switch C206-2, circuit CLN27 (WH/BN), harness side and ground. Is any voltage present? YES : Go to E3 . NO : Go to E2 .
2. E2 CHECK CIRCUIT CLN27 (WH/BN) FOR AN OPEN Key in OFF position. Disconnect: SJB C2280d Measure the resistance between the instrument panel dimmer switch C206-2, circuit CLN27 (WH/BN), harness side and the SJB C2280d-10, circuit CLN27 (WH/BN), harness side. Is the resistance less than 5 ohms? YES : Go to E5 . NO : REPAIR the circuit. TEST the system for normal operation.
3. E3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH Connect a fused (5A) jumper wire between the instrument panel dimmer switch C206-2, circuit CLN27 (WH/BN), harness side and the instrument panel dimmer switch C206-4, circuit GD161 (BK/YE), harness side. Do the interior lamps illuminate? YES : INSTALL a new instrument panel dimmer switch. REFER to «INSTRUMENT CLUSTER AND PANEL ILLUMINATION»(ref-268796) . TEST the system for normal operation. NO : REMOVE the jumper wire. Go to E4 .
4. E4 CHECK CIRCUIT GD161 (BK/YE) FOR AN OPEN Measure the resistance between the instrument panel dimmer switch C206-4, circuit GD161 (BK/YE), harness side and ground. Is the resistance less than 5 ohms? YES : Go to E5 . NO : REPAIR the circuit. TEST the system for normal operation.
5. E5 CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: corrosion pushed-out pins Connect all the SJB connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new SJB. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-268767) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.