Fog lights on with DRL in Auto Headlight mode - WORKING

[Underwhere]

Anyone know of a way to have the fog lights on by default?

I prefer to drive with fogs and DRL but in auto mode so I don't need to worry about turning on the headlights.

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[Static]

It's been a while but I think I was able to enable fogs as drl in forscan on a 21 xl. I have since changed the drl to some led turn bulbs I installed as I couldn't find decent LED fog bulbs that didn't go bad after a few months. All that's to say I believe it's possible

 

[Dover]

I leave my lights on auto and I push in the knob to turn on the fog lights. Automatically they both turn on

 

[Underwhere]

I leave my lights on auto and I push in the knob to turn on the fog lights. Automatically they both turn on

If I leave mine on auto, the DRL turn on but not the fogs.

Once it gets dark enough, the headlights turn on AND the fogs.

I'm trying to get the fogs to go with the DRL.

 

[Dakar09]

I don't think you can have fogs on automatically with DRLs. No car I've ever owned had the fog/driving lights come on with the DRLs. Probably a "safety issue" because driving lights used to pull a lot of juice (before LEDs) and needed their own relays so fuses didn't blow...and if they were on the same circuit as the DRLs those would stop working, too if a fuse blew. Then our overlords would be angry your DRLs were off and you were a menace to society.

 

[TexasTruckGuy]

I don’t even have the LED driving lights now. I disabled them because one side burned out. I wish there was a way to replace only the LEDs and not have to replace the whole headlight. I hate driving around with only part of them working tho so I finally just disabled them.

 

[Walter Townsend]

A couple of mods I did with forscan, was to enable Bambi Mode. This allows the driving / fog lights to stay on when the High Beams are in use, instead of shutting off whenever high beams come on and only operating with the low beams.

The other mod was to enable the rear driving lights to operate with the DRL Daytime Running Lights, that way you have lights in all four corners any time the vehicle is in motion, which can really increase safety especially in some sunlight glare situations.

 

[SilverPigeon]

Anyone know of a way to have the fog lights on by default?

I prefer to drive with fogs and DRL but in auto mode so I don't need to worry about turning on the headlights.

If you want to try it in FORScan: in the BCM:

				Fog_Lamp_Usage_Cfg (FLUC)
726-39-01	x*xx	xxxx	xx--	0 =	FLUC FOG_CORNERING		2 =	FLUC FOG_DRL_CORNERING
				1 =	FLUC FOG_DRL		3 =	FLUC FOG_ONLY

Set to 2. You may also need: in the BCM

				LF_Fog_Lamp_Ckt_Usage_Cfg (LFFLCUC)
726-42-01	xxxx	x*xx	xx--	0 =	LFFLCUC NOT_USED		3 =	LFFLCUC FOG_DRL_CORNERING
				1 =	LFFLCUC FOG_CORNERING		4 =	LFFLCUC FOG_ONLY
2 =	LFFLCUC FOG_DRL		5 =	LFFLCUC POWER_SUPPLY
				RF_Fog_Lamp_Ckt_Usage_Cfg (RFFLCUC)
726-42-01	xxxx	xxx*	xx--	0 =	RFFLCUC NOT_USED		3 =	RFFLCUC FOG_DRL_CORNERING
				1 =	RFFLCUC FOG_CORNERING		4 =	RFFLCUC FOG_ONLY
2 =	RFFLCUC FOG_DRL		5 =	RFFLCUC POWER_SUPPLY

Both set to 3. You may also need: in the BCM:

				DRL_WithFog_Cfg (DRLWFC)
726-38-02	x*xx	xxxx	xx--	0 =	DRLWFC ALLOW		1 =	DRLWFC INHIBIT

Set to 0.
There may be others, but start there.

 

[Underwhere]

If you want to try it in FORScan: in the BCM:

				Fog_Lamp_Usage_Cfg (FLUC)
726-39-01	x*xx	xxxx	xx--	0 =	FLUC FOG_CORNERING		2 =	FLUC FOG_DRL_CORNERING
				1 =	FLUC FOG_DRL		3 =	FLUC FOG_ONLY

Set to 2. You may also need: in the BCM

				LF_Fog_Lamp_Ckt_Usage_Cfg (LFFLCUC)
726-42-01	xxxx	x*xx	xx--	0 =	LFFLCUC NOT_USED		3 =	LFFLCUC FOG_DRL_CORNERING
				1 =	LFFLCUC FOG_CORNERING		4 =	LFFLCUC FOG_ONLY
2 =	LFFLCUC FOG_DRL		5 =	LFFLCUC POWER_SUPPLY
				RF_Fog_Lamp_Ckt_Usage_Cfg (RFFLCUC)
726-42-01	xxxx	xxx*	xx--	0 =	RFFLCUC NOT_USED		3 =	RFFLCUC FOG_DRL_CORNERING
				1 =	RFFLCUC FOG_CORNERING		4 =	RFFLCUC FOG_ONLY
2 =	RFFLCUC FOG_DRL		5 =	RFFLCUC POWER_SUPPLY

Both set to 3. You may also need: in the BCM:

				DRL_WithFog_Cfg (DRLWFC)
726-38-02	x*xx	xxxx	xx--	0 =	DRLWFC ALLOW		1 =	DRLWFC INHIBIT

Set to 0.
There may be others, but start there.

Awesome!
I will try in a few days.

Out of curiosity how does someone become knowledgeable about this stuff? Is it something I can figure out on my own?

 

[SilverPigeon]

As far as what the description of each configuration: inference, testing the hypotheses raised by that, having an understanding of which modules perform which functions. For example: the BCM controls general lighting functions. You can tell that by trawling through the spreadsheet for the BCM. There is no "cheat sheet" for the meaning of each configuration, but "DRL with FOG" becomes logical as the place to start. From there it's just knowledge borne of experience.

To understand more about the configuration addresses, blocks and values, have a look at livnitup's tutorial first, then have a read of the primer in my signature.

 

[Underwhere]

If you want to try it in FORScan: in the BCM:

				Fog_Lamp_Usage_Cfg (FLUC)
726-39-01	x*xx	xxxx	xx--	0 =	FLUC FOG_CORNERING		2 =	FLUC FOG_DRL_CORNERING
				1 =	FLUC FOG_DRL		3 =	FLUC FOG_ONLY

Set to 2. You may also need: in the BCM

				LF_Fog_Lamp_Ckt_Usage_Cfg (LFFLCUC)
726-42-01	xxxx	x*xx	xx--	0 =	LFFLCUC NOT_USED		3 =	LFFLCUC FOG_DRL_CORNERING
				1 =	LFFLCUC FOG_CORNERING		4 =	LFFLCUC FOG_ONLY
2 =	LFFLCUC FOG_DRL		5 =	LFFLCUC POWER_SUPPLY
				RF_Fog_Lamp_Ckt_Usage_Cfg (RFFLCUC)
726-42-01	xxxx	xxx*	xx--	0 =	RFFLCUC NOT_USED		3 =	RFFLCUC FOG_DRL_CORNERING
				1 =	RFFLCUC FOG_CORNERING		4 =	RFFLCUC FOG_ONLY
2 =	RFFLCUC FOG_DRL		5 =	RFFLCUC POWER_SUPPLY

Both set to 3. You may also need: in the BCM:

				DRL_WithFog_Cfg (DRLWFC)
726-38-02	x*xx	xxxx	xx--	0 =	DRLWFC ALLOW		1 =	DRLWFC INHIBIT

Set to 0.
There may be others, but start there.

Thanks!
It worked great.
I made a change to BCM 726-39-01 and that's all that was needed.
Now the truck lights (on auto) will turn on the LED DRL and the fog lights together.

I did NOT need to change 726-42-01 at all.
I already had 726-32-02 set to allow fogs with DRL (it just didn't work on Auto)

 

[Porpoise Hork]

I don’t even have the LED driving lights now. I disabled them because one side burned out. I wish there was a way to replace only the LEDs and not have to replace the whole headlight. I hate driving around with only part of them working tho so I finally just disabled them.

Could try one of these. Direct replacement for the oem quad LED headlights.

https://www.ebay.com/itm/146602268723?_trksid=p4375194.c102727.m162921



Probably.

 

[CAD_Jockey]

Thanks!
It worked great.
I made a change to BCM 726-39-01 and that's all that was needed.
Now the truck lights (on auto) will turn on the LED DRL and the fog lights together.

I did NOT need to change 726-42-01 at all.
I already had 726-32-02 set to allow fogs with DRL (it just didn't work on Auto)

Can you still turn the fogs off with the switch if you want?

 

[Underwhere]

Can you still turn the fogs off with the switch if you want?

That's a great question. I don't think it was switchable while in auto mode.

 

[Underwhere]

That's a great question. I don't think it was switchable while in auto mode.

I am not able to shut off the fogs when in auto mode (and it is daytime and running DRL)

But I also didn't try editing 726-42-01

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