Foglights Auto On

Lamby66 · June 5, 2018

Yoderrm, do you have the auto dimming headlight option? If you do not, the circuit is much easier. You just need too take the ignition feed and reverse the polarity with a relay (like I did) then diode protect that to the fog lights circuit. Then your fog lights would be on whenever the truck is running. Which I think is what you wanted. The problem is if you auto dimming headlights, they can not know the foglights are on or they wont go to high beam on their own

I dont have the circuit numbers here but if you give me a day, I should be able to look it up at work tomorrow

Sorry to dig up an old thread...

I currently have the 10/22 diode jump on my 2018 Silverado, as posted by [mention=57382]Spurshot[/mention]. It'll work for now, but isn't exactly what I'm looking for long-term.

Ideally, I want the fogs to "auto" on, regardless of day or night, low beam or high beam (10/22 diode only turns them on at night). However, I want to be able to turn on my parking lights at the boat ramp without turning on my fogs (10/22 diode doesn't allow this). This seems similar to what the OP was hoping for.

The original [mention=162629]Lamby66[/mention] circuit gets close, but wouldn't come on during the day with DRLs, if I'm understanding it right.

Only thing I can think to do is to use three diodes: one from high beams to fogs (X5-18 to X5-10), one from low beams to fogs (X4-1 to X5-10), and one from DRLs to fogs (X4-7 to X5-10). This should keep the fogs on during daytime with DRLs, and at night with both low beams or high beams. Then, at the boat ramp, I can turn my knob from auto to parking lights, which shouldn't trigger the fogs unless I press the fog switch.

Sorry if this was covered in the foglights to high beams thread... I tried to go through all of it.

Has anyone tried this on the 16-18 Silverados? Not sure if it will work since DRLs and parking lights are technically the same light, albeit different signals. Or does anyone have any other ideas? I've got a few more diodes laying around, and hope to try it this week if I get some time.

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yoderrm · June 5, 2018

No, I don't have the auto dimming/brights.

If you do a reverse ignition feed, are you able to turn off the fogs? I would want to turn them off at the boat ramp in the mornings, but leave the parking lights on.

Lamby66 · June 5, 2018

I can set you up with a circuit that can do that. The relay can auto latch and then the logic of the switch would release it. That is the way my circuit works. The only thing different with my circuit is I do not want my fog lights on during the day. No point in my eyes.

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yoderrm · June 5, 2018

Yeah, I understand I'm probably in the minority (as usual) for wanting them on in the day. For me, it's half for safety and half aesthetics. Not a deal breaker, but my preference.

I appreciate you looking into a circuit. If I get off work at a decent time tomorrow I might try the diodes and see what it does.

Lamby66 · June 6, 2018

Yeah, I understand I'm probably in the minority (as usual) for wanting them on in the day. For me, it's half for safety and half aesthetics. Not a deal breaker, but my preference.

I appreciate you looking into a circuit. If I get off work at a decent time tomorrow I might try the diodes and see what it does.

I can get you a circuit that works if your soldering and wiring skills are decent.

I will post it when I figure out the BCM point for the fog lamp switch.

Once you press the fog light switch, the foglights will turn off then can be turned back on via the switch. The automatic on circuit will not reset until the power is killed. Is that okay?

DO NOT DIODE THE LOW BEAM CIRCUIT!!! that is a control HIGH output circuit. The logic low control circuits are not designed to accept voltage!!!!

My schematic (posted earlier) used a relay as a logic inverter to make the high beams generate a logic low so I can use for the fog lamp control.

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Lamby66 · June 6, 2018

Oops, I said that wrong... the high beam circuit is fine. It's the low beam circuit that is a 12v control voltage.. that is the one needs the inverter!!!

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GRUMPE · June 6, 2018

On ‎3‎/‎28‎/‎2017 at 1:10 PM, Coby7 said:

Why would you need to turn them off once they're on? I did the simple diodes to low beam and DRLs and I'm happy with that, never feel the need to turn them off. They still turn ''OFF'' with high beams though.

This may be what I'm looking for.

I would like the fog lights to come on with the DRL's in the day time and at night be on with the drl's and the low beams.

Basically I want them on all the time that I am driving.

I just like the way the truck looks with them on.

If this is how you did yours can u please send me the link, I have a 2018

yoderrm · June 6, 2018

I noticed the wire for the low beams was heavier guage. I never got further than finding the bcm diagram and identifying the wires before it got dark outside. For some reason, I couldn't trick the ambient light sensor with a flash light, so I was never able to test the daytime running light signal.

My soldering and wiring skills are fine, I'm just incredibly ignorant at electronic circuits, haha. I really appreciate your help!

Just so I'm clear on what you're saying:

Upon startup, foglights will automatically come on, no matter what.

At any time, pressing the fog light switch turns them off. Pressing again turns them back on.

Turning the truck off, then back on, will reset the circuit and turn the lights back on.

Correct?

GRUMPE · June 6, 2018

On ‎5‎/‎31‎/‎2017 at 4:10 PM, Coby7 said:

I still find the 2 diode setup works great, fog lights come on with DRL and low beam.

please repost the link for this. This is what I am looking for. Sorry if its been posted before, this is my first day on this site so still getting use to the set up.

Thanks in advance

Lamby66 · June 6, 2018

Here is a circuit that SHOULD work for what you need.

Verify that the x3-5 pin is 12v on ignition which it looks like it should be.

You will need a 12v 5a dpdt relay. They sell them on Amazon for like 8 bucks with the base (you can use it if you want or solder to the relay contacts)

Make sure you connect a diode across the coil of the relay to prevent ringing. The cathode (bar side) needs to be on the ignition side of the coil.

Operation:

Then the truck is driving day ot night, the parking lights are on (drl) this is on x5-22

When the truck is started the relay is de-energized and the normally closed contact bridges the drl to the X5-10 FOGLIGHT control (protected by the diode in x5-22

The fog lights will be on if the truck is driving, or the lights are on.

If you press the factory fog light switch (logic low at X1-15), the relay will close and stay latched due the normally opened contact on the 2nd circuit pulling the wiper to ground. This will isolate the diode between X5-22 and X5-10.

The relay will stay latched as long as there is power to the relay via X3-5 (verify that is a good ignition power source)

The fog lights will now function as factory fog lights. Not allowable to be in high beam and turned on and off by the switch.

When the ignition is reset, so is the relay. The truck will go back to auto foglight mode.

I take no responsibility for any actions that arise from you modifying your truck including blowing your BCM.

DO THESE MODS AT YOUR OWN RISK!!!

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yoderrm · June 6, 2018

Thanks, Lamby!

15 minutes ago, Lamby66 said:

Then the truck is driving day ot night, the parking lights are on (drl) this is on x5-22

One potential problem: on the 16-18 silverados, even though the DRLs and parking lights are the same lights, they appear to have different signals. I have the 10/22 jumper currently, and the fogs do not come on with the DRLs during the day. Once the DRLs dim and become "parking lights" (either by auto headlights coming on, or turning knob) the fog lights come on. That's why I was thinking I would need another diode from x4-7.

Does that make sense? Hopefully I'm understanding correctly.

Lamby66 · June 6, 2018

I noticed the wire for the low beams was heavier guage. I never got further than finding the bcm diagram and identifying the wires before it got dark outside. For some reason, I couldn't trick the ambient light sensor with a flash light, so I was never able to test the daytime running light signal.

My soldering and wiring skills are fine, I'm just incredibly ignorant at electronic circuits, haha. I really appreciate your help!

Just so I'm clear on what you're saying:
Upon startup, foglights will automatically come on, no matter what.
At any time, pressing the fog light switch turns them off. Pressing again turns them back on.
Turning the truck off, then back on, will reset the circuit and turn the lights back on.
Correct?

We are close. The automatic foglights are tied to the running lights. They are on when the truck is driving or the lights are on.

Pressing the fog light control might actually do two things the first time you press it.
1) it will energize and latch the relay removing the foglight always on mod.
2) it will probably tell the BCM to turn ON the fog lights and your dash symbol will light. Pressing it again will turn off the lights and then every additional press will turn them on or off.

When you turn of the truck it resets the relay. It will then allow the DRL mod to work again until next time the foglight button is pressed.

Make sense?

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Lamby66 · June 6, 2018

I understand. Did you check with the truck actually in drive? I think the DRL and parking light logic is the same. But you need to be in drive. I will have to see what the circuit you stated does but if it's a logic low when the drl circuit is on, it will work.

I think the lights circuit is a little complex though. There is a data line that goes between the bcm and the lights. I think the DRL circuit is data and not logic. There is a transmission is not in neutral pin too.. also might be an option for you. Again it it's a logic low. If it is, just use that instead of the X5-22 pin.

Thanks, Lamby!

One potential problem: on the 16-18 silverados, even though the DRLs and parking lights are the same lights, they appear to have different signals. I have the 10/22 jumper currently, and the fogs do not come on with the DRLs during the day. Once the DRLs dim and become "parking lights" (either by auto headlights coming on, or turning knob) the fog lights come on. That's why I was thinking I would need another diode from x4-7.

Does that make sense? Hopefully I'm understanding correctly.

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yoderrm · June 6, 2018

Yeah, I tested in drive... although the first time I didn't and thought I'd blown something, lol.

When the truck is in drive, here's what happens with the 10/22 diode on place:

In daylight, the DRLs come on. Fog lights do NOT come on automatically.

At night, auto headlights come on. Fog lights come on automatically, and cannot be turned off unless all lights are turned off by the knob.

Day or night, if I turn knob to parking lights or headlights, the fog lights come on automatically. They remain on if I turn on the highbeams, and cannot be turned off unless all lights are turned off.

Lamby66 · June 6, 2018

I understand. Did you check with the truck actually in drive? I think the DRL and parking light logic is the same. But you need to be in drive. I will have to see what the circuit you stated does but if it's a logic low when the drl circuit is on, it will work.

I think the lights circuit is a little complex though. There is a data line that goes between the bcm and the lights. I think the DRL circuit is data and not logic. There is a transmission is not in neutral pin too.. also might be an option for you. Again it it's a logic low. If it is, just use that instead of the X5-22 pin.

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I think X4-7 is data looking at the circuit. I think it controls the light control module. I dont think that will work for you.

You can check X4-23 out of park a d this should go logic low (it disables the adjustable pedals when you are driving) X5-22 with X4-23 and you should then have fog lights when ever the truck is not in park.. the isolation relay still would work the same.

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