Rear Fog Light Constantly On - Coding Issue? Or Wiring?

[Fitz]

Hi All,

I'm hoping someone can shed some light on this. I've recently picked up a Supra (Build date: Jan 2020) and I've noticed that when the engine is running the car keeps the rear fog light on (also activates the rear fog in diagnostics mode). The rear fog button on the dash is switched off but responds and illuminates when pressed along with the message of "Rear Fog Light On" or "Rear Fog Light Off" but, it does nothing with the light as its always on. I've had a look through the Bimmercode forums and posts for the Supra and G29 Z4 but I can't seem to find anything relating to the Fog Light having constant power. It also looks like this is a unique issue as no one seems to have had this before. Surely there has to be a way to tell the module to only send power to the rear fog when the button is pressed? Unless, there is a wiring issue somewhere?

Any advice/suggestions are very welcome.

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[razorlab]

We have a rear fog light? Must be an EU thing.

 

[itzTang]

We have a rear fog light? Must be an EU thing.

you might be right. i remember people coding rear fog lights which eu already had it from factory. someone may have coded wrong to have them on all the time.

 

[Fitz]

We have a rear fog light? Must be an EU thing.

Yeah it's on EU Spec cars. The reverse light surrounds the fog in the UK/EU.

 

[itzTang]

o wait OP is from EU

 

[itzTang]

referring to this. not fog light. i mean drl light. Completely thinking of something else sorry! ignore my comments LOL!
https://www.supramkv.com/threads/tail-light-as-drl-possibility.13620/

 

[BMWAF]

Yeah it's on EU Spec cars. The reverse light surrounds the fog in the UK/EU.

+AU too.

 

[itzTang]

try disconnecting battery for a bit and reconnecting if not resolved try scanning for codes. might say. Some bmw lights stay on all the time when the tail light assembly itself is going out.

 

[razorlab]

Yeah it's on EU Spec cars. The reverse light surrounds the fog in the UK/EU.

I literally didn't even notice this was the UK section. Hah, my bad!

 

[Fitz]

try disconnecting battery for a bit and reconnecting if not resolved try scanning for codes. might say. Some bmw lights stay on all the time when the tail light assembly itself is going out.

I'll give it a go and see if anything changes. I've scanned for codes previously, nothing comes up.

 

[exe36m3]

As a guess, maybe it's a daytime running light (DRL) factory setting to have BOTH front and rear DRLs on for that market and Supra.

I found a thread earlier this week around turning *on* the REAR DRL with coding as some European markets had it and some didn't.

The YouTube poster showed that the lights are ON in the rear, like the fronts whenever the front DRLs were ON too.

Here's the video, see timestamp 4:30.

Since he coded it on, you should be able to code it off.

 

[BrettMRC]

I'll give it a go and see if anything changes. I've scanned for codes previously, nothing comes up.

Suspect some absolute spunk bucket has coded it to be always on via Bimmercode!

 

[MK5_Ger]

Suspect some absolute spunk bucket has coded it to be always on via Bimmercode!

A year ago I tried to find the rear fog light in Bimmercode.
I wanted it to light up as a coming home light and maybe as brake force display.
Since the REM doesn't exist anymore in G series cars I searched in the BDC. Didn't find anything there.

If you have the channel let me know

 

[Fitz]

Suspect some absolute spunk bucket has coded it to be always on via Bimmercode!

That is exactly my fear. The issue I have is that I've looked through Bimmercode and can't find anything that looks like it has anything to do with Fog lights or changing the way they operate. Opened up Expert Mode, but that just looks like the Matrix to me.

Ideally, I need to find someone who knows what the module/coding parameters are and be able to revert it back to stock or just tell it to not come on unless the button is pushed. Currently, can't find anyone.

 

[MK5_Ger]

That is exactly my fear. The issue I have is that I've looked through Bimmercode and can't find anything that looks like it has anything to do with Fog lights or changing the way they operate. Opened up Expert Mode, but that just looks like the Matrix to me.

Ideally, I need to find someone who knows what the module/coding parameters are and be able to revert it back to stock or just tell it to not come on unless the button is pushed. Currently, can't find anyone.

You might have to select the Z4 G29 in Bimmercode to see more modules.
The Supra only has a very limited selection.
I had to use the G29 to do some coding.

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