Forscan experts? No fog lights!

optionizerSS · Aug 26, 2025

So last fall my BCM went bad in my 2005 GT (Roush Sport). Replaced it with one with the exact same part number and everything works except my fog lights. The ones in the bumper and the ones in the grille. Neither work. Assuming the BCM needs flashed for that? I have Forscan and the adapter but when I open it up there is no BCM or anything similar showing. I deleted the existing profile in Forscan and saved a new one but still nothing.
I'll post pics of what I see in Forscan. I have the free version but renewed the free extended license today.
It only shows 2 that are non-asbuilt and those are ACM and GEM modules. And under each of those only shows a couple of things. Any help? How can I get these fog lights working again? I already checked all fuses unless I missed something.

Noobz347 · Aug 27, 2025

Not an expert but I stayed at a Holiday Inn one time.

Confirm power & ground first
- Check Fuse F39 (15A, fog lamps feed).
- Check relay inside the SJB (it’s integral, not serviceable separately).
- Verify you have power at the fog lamp connector with the switch on.
Fog lamp switch
- Make sure the fog lamp button/switch on the headlight switch is actually commanding. If the switch is bad, the SJB won’t trigger the relay.
Programming issue
- If the donor SJB came from a car that didn’t have fog lamps, they won’t work until the SJB is configured for it.
- That’s an as-built programming job → you’ll need to load your car’s original as-built data (from Ford’s Motorcraft Service site) into the replacement SJB.
FORScan limitation
- The free/standard version sometimes won’t show the SJB in 05–09 cars.
- You need the extended license (which you said you renewed) and a solid adapter (OBDLink EX is the reliable one). Some cheap ELM327 clones don’t communicate well with the SJB.
- Once connected, you should see SJB/SJB As-Built under the modules list.

If FORScan still won’t show the module, IDS (dealer tool) or a shop with access can do it.

You’ll need to use FORScan (with extended license + good adapter) to write the proper as-built data into it.

The fogs are controlled by the SJB, not a standalone relay you can swap.

optionizerSS · Aug 27, 2025

Noobz347 said:
Not an expert but I stayed at a Holiday Inn one time.

Confirm power & ground first

Check Fuse F39 (15A, fog lamps feed).

Check relay inside the SJB (it’s integral, not serviceable separately).

Verify you have power at the fog lamp connector with the switch on.

Fog lamp switch

Make sure the fog lamp button/switch on the headlight switch is actually commanding. If the switch is bad, the SJB won’t trigger the relay.

Programming issue

If the donor SJB came from a car that didn’t have fog lamps, they won’t work until the SJB is configured for it.

That’s an as-built programming job → you’ll need to load your car’s original as-built data (from Ford’s Motorcraft Service site) into the replacement SJB.

FORScan limitation

The free/standard version sometimes won’t show the SJB in 05–09 cars.

You need the extended license (which you said you renewed) and a solid adapter (OBDLink EX is the reliable one). Some cheap ELM327 clones don’t communicate well with the SJB.

Once connected, you should see SJB/SJB As-Built under the modules list.

If FORScan still won’t show the module, IDS (dealer tool) or a shop with access can do it.

You’ll need to use FORScan (with extended license + good adapter) to write the proper as-built data into it.

The fogs are controlled by the SJB, not a standalone relay you can swap.

Thanks for that info. That might help some. I was under the impression it was a non As-built category. Either way it still doesn't show up. But i have 2 2005 Roush's and i have swapped the relays with no luck. i'll double check to be sure i swapped the right ones cause i tried it a few months ago and don't remember everything i tried. as for the adapter, i bought one that was recommended by forscan so it should be good to go there. i also should have the original file i exported from the original SJB but would rather start with a known good one in case there was any corruption. i just don't want to brick anything...lol. Thanks!

optionizerSS · Aug 27, 2025

i just hooked it up to my other 2005 Roush and forscan doesn't show BCM or SJB on it either. get the exact same modules listed and everything works on that one

KRUISR · Aug 27, 2025

I have not used Forscan on a Mustang but have on other Fords. One of them was an 04 Ford Escape. That model didn't list a BCM either, but did have the GEM module with similar functions listed as a BCM, only less of them - fewer choices to change. I know on some older F150s (pre-2011s) won't show a BCM either.

I would follow the wiring. Check each connection from battery through switch through fog lights. Do you have power where you should have power. If not, start they with why.

optionizerSS · Aug 27, 2025

KRUISR said:
I have not used Forscan on a Mustang but have on other Fords. One of them was an 04 Ford Escape. That model didn't list a BCM either, but did have the GEM module with similar functions listed as a BCM, only less of them - fewer choices to change. I know on some older F150s (pre-2011s) won't show a BCM either.

I would follow the wiring. Check each connection from battery through switch through fog lights. Do you have power where you should have power. If not, start they with why.

I could check all that but my thought process is that everything worked until I replaced the BCM. That leads me to believe it is a programming issue. I did have to re-program my FOBS but other than that everything worked except the fog lights

KRUISR · Aug 27, 2025

When you installed the new BCM, did you put the old program into the new module?

Noobz347 · Aug 27, 2025

optionizerSS said:
I could check all that but my thought process is that everything worked until I replaced the BCM. That leads me to believe it is a programming issue. I did have to re-program my FOBS but other than that everything worked except the fog lights

I am fairly certain that you are correct.

Aside from getting assistance from Ford, I'm not sure what else is to be done about it.

optionizerSS · Aug 27, 2025

KRUISR said:
When you installed the new BCM, did you put the old program into the new module?

I did not. The part number was a match and at first glance I thought everything was working until a few weeks later when I tried to turn the fog lights on

KRUISR · Aug 27, 2025

When I have swapped ABS modules on my F150 I had to reprogram the replacement module with the AS BUILT program/parameters from my original module (or factory AS BUILT file - can be downloaded from Ford with your VIN). Otherwise codes and errors occurred.

Noobz347 · Aug 27, 2025

KRUISR said:
When I have swapped ABS modules on my F150 I had to reprogram the replacement module with the AS BUILT program/parameters from my original module (or factory AS BUILT file - can be downloaded from Ford with your VIN). Otherwise codes and errors occurred.

This is correct.

optionizerSS · Aug 27, 2025

And I can do that with Forscan?

Noobz347 · Aug 27, 2025

Sections 3 and 4 above.

optionizerSS · Aug 27, 2025

Noobz347 said:
Sections 3 and 4 above.

Thanks. I'll wait till end of cruising season and after I get a job to mess with it just in case I break something and have to call in an expert to fix it

lenko · Sep 6, 2025

I've got an 06 GT and the only thing I programmed with Forscan is turning off my DRLs. I have the latest 2.4.18 Lifetime Forscan and OBDLink EX, and as well I only have the Gem and the items you posted. Might be limited because I have a Saleen S/C and Brenspeed tune. I did quite a bit with the 2015 Lincoln MKC I had but there wasn't much I could do with the 2006 Mustang GT. And I didn't want to try to update anything and risk messing with my tune.

optionizerSS · Sep 6, 2025

lenko said:
I've got an 06 GT and the only thing I programmed with Forscan is turning off my DRLs. I have the latest 2.4.18 Lifetime Forscan and OBDLink EX, and as well I only have the Gem and the items you posted. Might be limited because I have a Saleen S/C and Brenspeed tune. I did quite a bit with the 2015 Lincoln MKC I had but there wasn't much I could do with the 2006 Mustang GT. And I didn't want to try to update anything and risk messing with my tune.

Yeah seems the line i need to change is in the as built GEM file. i'm gonna wait till after cruise season to try to restore it

lenko · Sep 6, 2025

Just note the change you make and if it doesn't work-change it back to what it was. Don't know if you saw this site in Forscan, but it deals some with DRLs and other lights so it may give you some ideas for your fix: https://forscan.org/forum/viewtopic.php?f=6&t=2256&p=9806&hilit=2006+Mustang+drl#p9806. I needed DRLs here in Canada and as I had installed a GT500Front clip, I was able to rewire to DRLs to my Fog lamps of that front. There are links to how I did that and where the idea came from.

optionizerSS · Sep 7, 2025

lenko said:
Just note the change you make and if it doesn't work-change it back to what it was. Don't know if you saw this site in Forscan, but it deals some with DRLs and other lights so it may give you some ideas for your fix: https://forscan.org/forum/viewtopic.php?f=6&t=2256&p=9806&hilit=2006+Mustang+drl#p9806. I needed DRLs here in Canada and as I had installed a GT500Front clip, I was able to rewire to DRLs to my Fog lamps of that front. There are links to how I did that and where the idea came from.

Interesting read. That should help me later but I need to figure out which values to change for the fog lights. I could try uploading the entire as-built file from the internet but I'd prefer to only change the one value I need since everything else is working fine. Anyone know which value is for fog lights (both the in bumper and in grill as neither are working)?

lenko · Sep 7, 2025

"Anyone know which value is for fog lights (both the in bumper and in grill as neither are working)?"
Is that a Roush front end with TWO SETS of fog lamps? Were all four turn on all at once or two individually? The original GT As-builts would likely only be programmed for the grille fog lamps. It seems that Roush then would have somehow activated or rewired the bumper fog lamps.

optionizerSS · Sep 7, 2025

lenko said:
"Anyone know which value is for fog lights (both the in bumper and in grill as neither are working)?"
Is that a Rousch front end with TWO SETS of fog lamps? Were all four activated all at once or separately? The original GT As-builts would likely only be programmed for the grille fog lamps. It seems that Rousch then would have somehow activated or rewired the bumper fog lamps.

Yes it is a Roush. I didn't realize the GT didn't have the lower bumper fog lights? I have 2 2005 Roush's, If I knew where to look I could probably grab the values from the other one?

Forscan experts? No fog lights!

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