When I began researching potential causes of my puddle light and steering wheel illumination outage, I quickly realized that it was a fairly common occurrence, most often without resolution. Bits of information were scattered among various resources that were helpful in totality, but the process of information gathering was inefficient and lacked process-driven troubleshooting. The purpose of this post is to share what I have learned on this topic in a manner that will be useful to everyone, regardless of technical aptitude. I encourage feedback in this thread to keep it honest and informative.
My Symptoms:
One evening I noticed that my steering wheel buttons weren’t illuminating. In the seconds that followed I questioned if they were supposed to light up in the first place. The manual indicated Fuse 10 (15A) for switch backlighting, which also powered the puddle lights. Indeed, both were affected. In my case, F10 was not blown and my troubleshooting journey would lead me down an enlightening path. Also unnoticed at the time was that the following illumination was also lost: adjustable pedal switch, message center/power liftgate/traction control/hazard buttons, overhead console buttons, floor shifter, headlamp switch, 4WD switch, and second row climate control.
Low Hanging Fruit:
Having the dimmer switch in the OFF position could mimic this condition. It’s the stop position, past the detent when rotating the dial downward. If the dimmer setting was the problem, congratulations! For the rest of us, observe if your interior lights, instrument cluster and front climate control lighting responds to the dimmer. More on this later.
The Circuit:
The 2013 Expedition employs a Generic Electronic Module, which is also referred to as a Smart Junction Box. Those references can be used interchangeably and will be abbreviated to GEM/SJB. The basic purpose of this module is to control various electronic circuits, including puddle lights and backlighting. The module is also connected to MS-CAN and can be communicated using FORScan, capable bidirectional scanner, and Ford IDS/FJDS with an appropriate Vehicle Communications Interface (VCI).
The GEM/SJB internally utilize Field-Effect Transistors (FETs) to switch various circuits on/off, and to also monitor the state of those circuits. For the purpose of this post, those FETs are non-serviceable. FETs will disable individual outputs if excessive current is detected, which is typically caused by a short circuit. A DTC will be stored when this occurs and the module keeps count of repeated occurrences. This is important because each FET has a lifetime tolerance and can reach a point where DTCs can no longer be cleared to restore circuit functionality. Until that threshold is reached, it would be possible to correct the cause of the short, clear the DTC, and initiate an on-demand self-test using FORScan, scan tool, or Ford diagnostic tool to restore functionality. Note that short circuits will set DTC B106E, which is resettable. If DTC B106F is present, then repeated failures have reached the maximum threshold and the affected circuit(s) will remain permanently disabled.
I found this forum thread while researching the issue, which linked to a YouTube video that was no longer viewable within the original post. It describes the process of using FORScan to reset the GEM/SJB to restore circuit functionality after DTC B2A3A (Puddle Lamp Output Circuit Short to Ground) was triggered. Any pre-existing short-circuit condition must first be remediated for this to be successful or the DTC would reoccur. The video is provided below for convenience.
My Case:
The circuit responsible for my puddle light and steering wheel illumination was likely “out” for a period of time before being noticed. There was no occasion prior to that when I observed any related DTCs or even had cause to scan the system. Subsequent scans did not reveal any stored or active DTCs related to the affected circuit.
As noted earlier, my dimmer switch was otherwise functional, which eliminated it as a potential cause. Essentially, the dimmer sends a low current variable voltage to one of the GEM/SJB inputs, which in turn varies the voltage for dimmable outputs. The dimming of unaffected circuits indicated that the module was receiving that proper input.
I then disconnected one of the puddle lights and verified source voltage. I was perplexed after observing a voltage reading in the range of 1V-3V (IIRC), but the required 12V was not present. I later determined that the low voltage reading was actually a bias voltage used by the circuit to actively monitor open, short, and impedance conditions. The latter can be important because some circuits expect a resistance reading within a specific range, and the module could register error conditions otherwise. Applying direct voltage to the puddle lights outside of the circuit confirmed that they were operational.
My next step was to eliminate the wiring harness. The puddle lights are powered by C2280C PIN-12, and the backlight circuits from C2280B PIN-39. Those pins are tightly arranged so I used an F-M Dupont jumper to prevent shorts. After connecting the multimeter FORScan or a capable scan tool can be used to manually activate those circuits to monitor voltage output. Using this approach also eliminates the possibility of input related issues to the GEM/SJB. As you may have guessed, I did not have proper voltage output on either circuit.
Diagnosis and Resolution:
I did not have DTC B106F, FORScan and my scan tool were indicating successful commands to activate both lighting circuits, yet I did not have proper voltage output at the connectors. Yep... the GEM/SJB required replacement. The original part was BL1T-15604-AB and the current replacement is BL1Z-15604-B. Online resources indicate that this module is common to Expedition/Navigator ranging from 2007 through 2014 but always verify your original part number to be certain. New modules will include all necessary fuses and the relay. I caution against used modules, but they are an option.
Fortunately, the module was easily accessible from the passenger kick panel. It is secured to the frame by two screws and has a total of seven connectors. Four of the front-facing connectors have locking levers, which must be in the fully unlocked position when being reinserted. Do not force the connector on reinsertion, closing the lever will continue to seat and lock it in place. The locking connector atop the module supplies power to the unit.
Unfortunately, this is not a plug-and-play operation. Replacement modules must be programmed to your vehicle. This can be accomplished in one of two ways, and possibly a third.
I invested in a Mongoose Ford2 J2534 VCI and a two-day (48hr) subscription to FJDS. I’m still peeved that the cost was more than my XTOOL D8BT, which claimed to have the same functionality. This Mongoose cable is specific to Ford vehicles and cannot be used for other makes. The higher-end J2534 solutions do not have that limitation. The length of this post has likely resulted in some casualties, so I will refrain from detailing the programming procedure. Just note that the original module should be installed in the vehicle to allow FJDS to retrieve its programming. You will be prompted to install the new module at the appropriate time, and there is no need to disconnect the vehicle battery during the procedure. Be patient and allow time for each step. Once the process is finished you will receive a message indicating that additional action is required to finalize the installation. Your interior lights should begin flashing and your gear shift will be locked in P.
New modules are shipped with 7 pre-set DTCs which will be detected once the programming phase is completed.
There was no need to reprogram keys since PATS is handled by the IPC. Note that a new GEM/SJB will include a card with a new default keyless entry code. You can also read the factory code from the module using the diagnostic tool. It will likely differ from the code on the card, so there are actually two preprogrammed factory keyless entry codes per module.
The following video walks through most of the programming steps using Ford IDS, which are very similar to FJDS.
Final Thoughts:
I have not been able to prove the theory, but I suspect that a common cause of this circuit failure is due to the installation of aftermarket LED puddle lights. The ones I installed were purchased from AliExpress and there are similar versions floating around Amazon. The modern Ford replacements (JU52-13B374-A) are LED, which are brighter than the original incandescents but produce marginally less output than the aftermarkets. Stick with OEM replacements since they will provide the proper impedance.
Please respond to the poll preceding this post if you are plagued with this issue. It would be interesting to see if there is a pattern related to aftermarket LEDs.
My Symptoms:
One evening I noticed that my steering wheel buttons weren’t illuminating. In the seconds that followed I questioned if they were supposed to light up in the first place. The manual indicated Fuse 10 (15A) for switch backlighting, which also powered the puddle lights. Indeed, both were affected. In my case, F10 was not blown and my troubleshooting journey would lead me down an enlightening path. Also unnoticed at the time was that the following illumination was also lost: adjustable pedal switch, message center/power liftgate/traction control/hazard buttons, overhead console buttons, floor shifter, headlamp switch, 4WD switch, and second row climate control.
Low Hanging Fruit:
Having the dimmer switch in the OFF position could mimic this condition. It’s the stop position, past the detent when rotating the dial downward. If the dimmer setting was the problem, congratulations! For the rest of us, observe if your interior lights, instrument cluster and front climate control lighting responds to the dimmer. More on this later.
The Circuit:
The 2013 Expedition employs a Generic Electronic Module, which is also referred to as a Smart Junction Box. Those references can be used interchangeably and will be abbreviated to GEM/SJB. The basic purpose of this module is to control various electronic circuits, including puddle lights and backlighting. The module is also connected to MS-CAN and can be communicated using FORScan, capable bidirectional scanner, and Ford IDS/FJDS with an appropriate Vehicle Communications Interface (VCI).
The GEM/SJB internally utilize Field-Effect Transistors (FETs) to switch various circuits on/off, and to also monitor the state of those circuits. For the purpose of this post, those FETs are non-serviceable. FETs will disable individual outputs if excessive current is detected, which is typically caused by a short circuit. A DTC will be stored when this occurs and the module keeps count of repeated occurrences. This is important because each FET has a lifetime tolerance and can reach a point where DTCs can no longer be cleared to restore circuit functionality. Until that threshold is reached, it would be possible to correct the cause of the short, clear the DTC, and initiate an on-demand self-test using FORScan, scan tool, or Ford diagnostic tool to restore functionality. Note that short circuits will set DTC B106E, which is resettable. If DTC B106F is present, then repeated failures have reached the maximum threshold and the affected circuit(s) will remain permanently disabled.
I found this forum thread while researching the issue, which linked to a YouTube video that was no longer viewable within the original post. It describes the process of using FORScan to reset the GEM/SJB to restore circuit functionality after DTC B2A3A (Puddle Lamp Output Circuit Short to Ground) was triggered. Any pre-existing short-circuit condition must first be remediated for this to be successful or the DTC would reoccur. The video is provided below for convenience.
Video Title: 2007-2014 Ford Expedition Backlights, Steering Wheel, Puddle Lights, Gear Shift Lights Not Working
My Case:
The circuit responsible for my puddle light and steering wheel illumination was likely “out” for a period of time before being noticed. There was no occasion prior to that when I observed any related DTCs or even had cause to scan the system. Subsequent scans did not reveal any stored or active DTCs related to the affected circuit.
As noted earlier, my dimmer switch was otherwise functional, which eliminated it as a potential cause. Essentially, the dimmer sends a low current variable voltage to one of the GEM/SJB inputs, which in turn varies the voltage for dimmable outputs. The dimming of unaffected circuits indicated that the module was receiving that proper input.
I then disconnected one of the puddle lights and verified source voltage. I was perplexed after observing a voltage reading in the range of 1V-3V (IIRC), but the required 12V was not present. I later determined that the low voltage reading was actually a bias voltage used by the circuit to actively monitor open, short, and impedance conditions. The latter can be important because some circuits expect a resistance reading within a specific range, and the module could register error conditions otherwise. Applying direct voltage to the puddle lights outside of the circuit confirmed that they were operational.
My next step was to eliminate the wiring harness. The puddle lights are powered by C2280C PIN-12, and the backlight circuits from C2280B PIN-39. Those pins are tightly arranged so I used an F-M Dupont jumper to prevent shorts. After connecting the multimeter FORScan or a capable scan tool can be used to manually activate those circuits to monitor voltage output. Using this approach also eliminates the possibility of input related issues to the GEM/SJB. As you may have guessed, I did not have proper voltage output on either circuit.
Diagnosis and Resolution:
I did not have DTC B106F, FORScan and my scan tool were indicating successful commands to activate both lighting circuits, yet I did not have proper voltage output at the connectors. Yep... the GEM/SJB required replacement. The original part was BL1T-15604-AB and the current replacement is BL1Z-15604-B. Online resources indicate that this module is common to Expedition/Navigator ranging from 2007 through 2014 but always verify your original part number to be certain. New modules will include all necessary fuses and the relay. I caution against used modules, but they are an option.
Fortunately, the module was easily accessible from the passenger kick panel. It is secured to the frame by two screws and has a total of seven connectors. Four of the front-facing connectors have locking levers, which must be in the fully unlocked position when being reinserted. Do not force the connector on reinsertion, closing the lever will continue to seat and lock it in place. The locking connector atop the module supplies power to the unit.
Unfortunately, this is not a plug-and-play operation. Replacement modules must be programmed to your vehicle. This can be accomplished in one of two ways, and possibly a third.
- Scan Tool – some of the higher-end bidirectional scan tools allow programming of various modules. Such functionality correlates to higher cost. Your $500 scan tool is not likely to have that capability. I am going to rant a bit and mention that I own the XTOOL D8BT. It has several features that are typically exclusive to more expensive scan tools. However, it boasts ‘Programmable Module Installation’ for the GEM/SJB and it simply does not work. The D8BT performs some sort of abbreviated installation that leaves the vehicle in an undrivable state. I heard great things about their technical support and how they provided firmware updates within a couple of days to address specific issues. I reported this problem in detail and they have failed to respond beyond acknowledging my communication. Perhaps their D9 Pro would have been more capable but it is double the cost.
- FORD IDS/FJDS/FDRS – Ford provides dealer level diagnostic and programming capabilities using their subscription based software. The notable distinction between IDS and FJDS/FDRS is that the former requires Ford’s VCM, VCM II, or VCMM. That hardware is very expensive and I would not recommend using any of the “affordable clones” due to risk of bricking modules. The Ford VCIs also work with FJDS and FDRS. You can also use FJDS and FDRS with a compatible J2534 adapter. Again, I would avoid unsupported adapters. These J2534 alternatives cost less than the VCMs and range from $500+ to $3000+ depending on specific needs.
- FORScan – I believe the more current versions support limited module programming for some vehicles using a vLinker OBD2 or compatible J2534 adapter. I’ll be looking into this more.
I invested in a Mongoose Ford2 J2534 VCI and a two-day (48hr) subscription to FJDS. I’m still peeved that the cost was more than my XTOOL D8BT, which claimed to have the same functionality. This Mongoose cable is specific to Ford vehicles and cannot be used for other makes. The higher-end J2534 solutions do not have that limitation. The length of this post has likely resulted in some casualties, so I will refrain from detailing the programming procedure. Just note that the original module should be installed in the vehicle to allow FJDS to retrieve its programming. You will be prompted to install the new module at the appropriate time, and there is no need to disconnect the vehicle battery during the procedure. Be patient and allow time for each step. Once the process is finished you will receive a message indicating that additional action is required to finalize the installation. Your interior lights should begin flashing and your gear shift will be locked in P.
New modules are shipped with 7 pre-set DTCs which will be detected once the programming phase is completed.
- B2477 - GEM/SJB Module Configuration Failure
- C2780 - ECU in Manufacturer Sub-State
- B106D - TPMS Not Configured
- B2868 - Left Front Tire Pressure Sensor Fault
- B2869 - Right Front Tire Pressure Sensor Fault
- B2870 - Right Rear Tire Pressure Sensor Fault
- B2871 - Left Rear Tire Pressure Sensor Fault
There was no need to reprogram keys since PATS is handled by the IPC. Note that a new GEM/SJB will include a card with a new default keyless entry code. You can also read the factory code from the module using the diagnostic tool. It will likely differ from the code on the card, so there are actually two preprogrammed factory keyless entry codes per module.
The following video walks through most of the programming steps using Ford IDS, which are very similar to FJDS.
Video Title: 2011 Ford Expeditions GEM/Smart Junction Box Replacement and Programming - Step By Step Using IDS
Final Thoughts:
I have not been able to prove the theory, but I suspect that a common cause of this circuit failure is due to the installation of aftermarket LED puddle lights. The ones I installed were purchased from AliExpress and there are similar versions floating around Amazon. The modern Ford replacements (JU52-13B374-A) are LED, which are brighter than the original incandescents but produce marginally less output than the aftermarkets. Stick with OEM replacements since they will provide the proper impedance.
Please respond to the poll preceding this post if you are plagued with this issue. It would be interesting to see if there is a pattern related to aftermarket LEDs.
