Fog lights turn on with low beams

[Runn]

Hey all, I have a 2020 SLT Yukon, I'm curious if the fog lights can turn on with the low beams automatically? I've seen some pre 2014 articles showing that theres some harnesses for keeping them on when the high beams are on. But I personally wanted to have them on with the low beams. Right now, I have to press the button for them every time the lights are on or on auto. Am I just missing something?

 

[PG01]

Hey all, I have a 2020 SLT Yukon, I'm curious if the fog lights can turn on with the low beams automatically? I've seen some pre 2014 articles showing that theres some harnesses for keeping them on when the high beams are on. But I personally wanted to have them on with the low beams. Right now, I have to press the button for them every time the lights are on or on auto. Am I just missing something?

No, you have push button when you want them on. They don’t work with auto high, even when it switches back to low beam, but if you don’t have auto high on and push the fog button they will be on with lows, off with high. It is annoying imo. There prob is a resistor than can be wired in somewhere but I’m not sure if anyone has done it... @cmatt .... a little help???

 

[cmatt]

No, you have push button when you want them on. They don’t work with auto high, even when it switches back to low beam, but if you don’t have auto high on and push the fog button they will be on with lows, off with high. It is annoying imo. There prob is a resistor than can be wired in somewhere but I’m not sure if anyone has done it... @cmatt .... a little help???

It's a matter of keeping the fog lamp relay energized. The challenge is that it's a ground switched relay. So, if you have factory HIDs (also ground switched relay), then it's feasible that a diode could be used between the pins at the BCM to keep the fogs on.

Unfortunately, vehicles with factory halogen low beams use a PWM voltage that flows straight through (no fuse block relay). A custom relay harness that uses the low beam or park lamp circuit at the headlight as a trigger would be needed. Both methods would have their drawbacks in terms of headlight functionality. 2015-2017 Tahoe/Suburban would require additional consideration as the low beam is also used for DRL purposes.

In both scenarios, I'm unsure if the fog lamp indicator on the cluster would illuminate as it's an unconventional way to activate them.

 

[PG01]

It's a matter of keeping the fog lamp relay energized. The challenge is that it's a ground switched relay. So, if you have factory HIDs (also ground switched relay), then it's feasible that a diode could be used between the pins at the BCM to keep the fogs on.

Unfortunately, vehicles with factory halogen low beams use a PWM voltage that flows straight through (no fuse block relay). A custom relay harness that uses the low beam or park lamp circuit at the headlight as a trigger would be needed. Both methods would have their drawbacks in terms of headlight functionality. 2015-2017 Tahoe/Suburban would require additional consideration as the low beam is also used for DRL purposes.

In both scenarios, I'm unsure if the fog lamp indicator on the cluster would illuminate as it's an unconventional way to activate them.

Thanks Matt. I know you’re gmt900-ing nowadays but I’m dropping this k2 problem on you... ....lol

 

[cmatt]

Lol, keep ‘em coming. I won’t be slowing down on the K2XX platform, just adding the GMT 900 to the knowledge base. Biggest challenge is time with my day job.


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