Fogs on with lows and highs(pics inside)

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t.stimpson

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This didn't work on my 2009 denali. Not sure if my truck having led's effected it but when wiring the fogs to the headlamps the fogs were always on since the headlamps are the DRL's. I only wanted my fogs to come on with the headlamps at night, tired of manually turning them on. So instead I wired the fogs to the park light fuse relay. This has worked flawlessly for me. I also did not use a diode, just an 18 gauge wire. I can post a pic if anyone is interested.
 

KMeloney

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This didn't work on my 2009 denali. Not sure if my truck having led's effected it but when wiring the fogs to the headlamps the fogs were always on since the headlamps are the DRL's. I only wanted my fogs to come on with the headlamps at night, tired of manually turning them on. So instead I wired the fogs to the park light fuse relay. This has worked flawlessly for me. I also did not use a diode, just an 18 gauge wire. I can post a pic if anyone is interested.

Definitely interested in pics. Thanks!
 

Meccanoble

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Whats that other wire connected? You have 2 different wires setup. From image, its top left of fog and bottom right of park?
 

NGAneer

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Whats that other wire connected? You have 2 different wires setup. From image, its top left of fog and bottom right of park?

I did it with the diode on my 99 Silverado but for the Yukon I did it using a relay. Basically two circuits to turn the fogs on, one with the factory switch and the other with a relay trigger by the high beam circuit, it's a little more straight forward in my mind than trusting that the diode is doing it's job.
 

Meccanoble

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so all we need is a diode or a good size wire (12 gauge?) going from the fog relay to the low beam if we want fogs to always come on with low beam? Thickest wire would you use and nothing else is needed? I seen another wire setup in your image above.
 

RST Dana

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so all we need is a diode or a good size wire (12 gauge?) going from the fog relay to the low beam if we want fogs to always come on with low beam? Thickest wire would you use and nothing else is needed? I seen another wire setup in your image above.

My fogs already come on (with push button) on low beam, but turn off on high. I am looking at adding relays to allow them on on high and then hopefully the auto dim function will still function. Auto dim stops working while the fog light button is engaged.
 

Mickey_7106

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No. if you install any size wire between 2 circuits, electricity can flow in either direction freely. if a Diode is installed, electricity can flow in one direction freely, but it will have a higher resistance going the opposite way. Thats why diodes are sold with different ratings

so all we need is a diode or a good size wire (12 gauge?) going from the fog relay to the low beam if we want fogs to always come on with low beam? Thickest wire would you use and nothing else is needed? I seen another wire setup in your image above.
 

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