No foglight indicator after dead battery

[Le Mans]

Anyone familiar with the many sudden malfunctions after a dead battery? I have been able to reset most of them (no window heating, no passenger seat heating, ventilation, etc. but... I have no fog lamp indication in my dashboard. The fog lights (front and rear) do work. How do I get them visible again in my dashboard?

Mustang 2015 convertible Cervini

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[Skye]

So as to clarify, what fixed the dead battery situation? Replacement battery and/or other parts?

 

[Le Mans]

So as to clarify, what fixed the dead battery situation? Replacement battery and/or other parts?

Replace the battery. I
tried under power with battery charger on the cables, but a clamp came loose during change

 

[Skye]

Replace the battery.

Cool. Was a BMS reset accomplished afterwards?

https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/

 

[Le Mans]

Cool. Was a BMS reset accomplished afterwards?

https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/

Thank you dif I tried. battery indication actually flashed 3 times unfortunately no changes and no fog light indication yet

 

[ORRadtech]

Replace the battery. I
tried under power with battery charger on the cables, but a clamp came loose during change

FYI for future reference, there's no need to provide external power for a battery swap. You will not lose any settings from a quick swap.
I did not a couple of years ago when I swapped the Mustang battery. Nor did I lose anything this past week when I changed my Fusion battery. In order to avoid a core charge I took the battery out and with me. After other errands it was about 5 hours between removal and replacement. I lost no settings and had no odd anomalies.

 

[Torched10]

Anyone familiar with the many sudden malfunctions after a dead battery? I have been able to reset most of them (no window heating, no passenger seat heating, ventilation, etc. but... I have no fog lamp indication in my dashboard. The fog lights (front and rear) do work. How do I get them visible again in my dashboard?

Mustang 2015 convertible Cervini

Sound like fuse
Just as a lark you can turn on off by flipping the fog light on off switch
Here's a pic of switch.maybe that resets indicator light

 

[Le Mans]

Sound like fuse
Just as a lark you can turn on off by flipping the fog light on off switch
Here's a pic of switch.maybe that resets indicator light

Thank you very much for the tip Tried it right away, with ignition on, with ignition off, and with moror on, motor off, unfortunately no results.

Fog lights turn on and off, but no indication is visible

 

[Skye]

Reading through some like threads.

When you are turning the fog lights on and off, as you described in your last post, are the headlights on low? Low beams, yes?

Otherwise, I looked for a fuse, relay or something of the sort, hoping it could be temporarily removed so as to reset any logic issues. But I could not find one dedicated to fog lights.

 

[Torched10]

Reading through some like threads.

When you are turning the fog lights on and off, as you described in your last post, are the headlights on low? Low beams, yes?

Otherwise, I looked for a fuse, relay or something of the sort, hoping it could be temporarily removed so as to reset any logic issues. But I could not find one dedicated to fog lights.

Google said fuse 21 is fog lights
Being an ee but not car expert I'd think the fog lights must run a wire back to I NDcater or back to relay that switches on fog lights and also the I indicstor lightd.if you can get wiring diagram you can see how the display lights are powered

Then you'd have to look for a disconnected wire or Relay between fog lights and display
If lights are working if it were me I'd just put it out of my mind and move on.but I have my own issues with certain things making me crazy and I obsessive so I understand
Did you try light switch with high beam aS well
Good luck

Ps when you put car in acc mode do the fog light indicators light up

 

[Skye]

I've attached some schematics, to show relationships.

There are basically two pathways:

- One path goes from the Body Control Module A, (interior, right side, near floor) to the fog lights

- One path goes from the Body Control Module A to the headlight switch

https://www.fordservicecontent.com/...A&div=f&vFilteringEnabled=False&buildtype=web

I don't see where there is a dedicated fuse for fog lights, in either the 2015 or 2022 manuals They could be tied to the headlight circuit. IDK. I've never dug into this before.

Everyone is going to be different in how they approach things. Me, I'd leave it be. Maybe it'll work again. Maybe never. The problem started with a failed battery, which was replaced. I would not begin wire testing. I'd end up making it worse. YMMV.

I've read a few other older threads from other sites. It's often like a logic hang. One poster had FORSCAN access: he toggled off a related feature, toggled it back on and the problem resolved itself.

I'm qualified at the Fisher Price level , and will pause. But I am interested to see if the issue gets fixed.

 

[Le Mans]

Thanks guys,

when I turn on the fog lights, my normal lights are on. low beam (?)

If it was a fuse they wouldn't work at all right? Now I just don't see the indication.
Here in Holland it is an inspection item, the indication must work.

With the high beams on, I can also turn on the fog lights. It seems that after the battery voltage is too low, the switch needs to be relearned?

What do you mean by acc mode?

 

[Skye]

Normal lights are low beam, yes. Yes, fog lights should indicate being on when low beams are on.

I read some references that, if the high beams are on, the fog lights might not operate; it's a feature I believe to prevent from blinding anyone. It also mentioned if high beams are on, the fog lights would not indicate as such.

I can appreciate the inspection routine. Sorry I couldn't be of any better help.

One final thought I have: now that the battery is replaced and you've accomplished a BMS, disconnect the negative terminal of the battery, and let the car sit overnight. Letting it sit for several hours unpowered won't hurt. And it could allow whatever is hung up to completely de-energize and begin working correctly again.

 

[Le Mans]

I can try that.. thx


it's 23.00 pm here now. Tomorrow I will add some photos first.

maybe you see something else that can help

Thank you very much so far

 

[Torched10]

Thanks guys,

when I turn on the fog lights, my normal lights are on. low beam (?)

If it was a fuse they wouldn't work at all right? Now I just don't see the indication.
Here in Holland it is an inspection item, the indication must work.

With the high beams on, I can also turn on the fog lights. It seems that after the battery voltage is too low, the switch needs to be relearned?

What do you mean by acc mode?

I was thinking k I ng of my wife's car.in hers you can get display mode and and see all the indicators. Just tried my 19gt and it diesnt work that way.i used to work with Phillips alot when i was with att. So it doesn't surprise me that they regulate that minor an item.you might try calling the ford service number and see what they think.if you think it happened when battery was changed disconnect it again and see if it fixes itself.since you won't be able to pass inspection you'll need a dealer to try and fix it.im sure it won't be cheap it never is when they can't diagnose it easily
The diagram shows the wire going to the fog light is hot so there has to be a fuse sonewhere

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