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Discussion Starter #1
I've got an interesting issue I'm looking for a solution to.

I have no idea why I'm only encountering it now. From the research I've done I feel like it should have been an issue ever since I installed my driving lights but it wasn't. They worked fine.

Anyhow... I've got IPF driving lights and the relay uses the high-beam light wire to energize it. With the engine off it seems fine, but with the engine running it buzzes loud enough to hear it in the cabin.

I've done some searching and it seems this has to do with the modulation of the signal on that wire. Since it's not a steady 12v voltage it's causing havoc in the relay.

I found a couple threads about this on the AEV forums but no definitive solution.

This one has a bad diagnoses but they come up with the solution of using a steady 12v wire to energize. It's not a good solution because I really want them to turn on and off with the high-beam switch as they do now.

https://forum.aev-conversions.com/forum/all-aev-products/jk-parts-discussion-2007-jeep-wrangler/10885-led-headlight-help-ipf-relay-shorted

This one has a potential solution but I'm hoping someone here might be able to clarify and come up with something better.

https://forum.aev-conversions.com/forum/all-aev-products/jk-parts-discussion-2007-jeep-wrangler/1376-ipf-900xs-relay-buzz

Here's my direct question that I'm hoping someone here can answer: Is there a relay designed to work with a PWM signal that I could use to provide a steady 12v signal to my driving light wiring harness? I think that would solve all my problems.

I'm not talking about replacing the existing relay. I'm talking about adding a new one designed to work properly with the modulated voltage that would then send a steady 12v to the existing relay.

Edit: This has a good explanation of why putting a diode and capacitor in line to the existing relay should solve the problem but I have to believe there's a device that's designed to do this rather than having to hack a solution.

https://www.electronicspoint.com/forums/threads/trying-to-understand-pwm-solve-relay-buzz.290713/

Edit 2: Further reading suggests something called an RC filter does exactly what I need. It seems I just need to figure out what sort of RC filter I need.
 

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PWM is causing the issue. The relay is turning on/off hundreds of times per second as PWM varies in voltage.... which causes a buzzing noise. You can try adding a diode and a cap to the relay. The diode will act as a one way valve block power into the relay and not let it reverse while the cap *should* smooth out the PWM enough to stop it from vibrating.
 

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Discussion Starter #3
You're exactly right according to my research.

What I'm wondering is whether there's a device created to deal with this. Is there a relay with the stuff built in to let it behave in this scenario?

A diode is straight-forward but what sort of capacitor do I need and how do I add that in?
 

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I had a similar issue with my 09 when I swapped in my H4's. The first relay came out of my 05 headlight setup that I took with me when I sold it. It worked fine with the PWM but the contacts started sticking and eventually the headlights would not shut off. So I got another relay and that chattered and would not turn on the headlights. I added a truck-lite anti chatter harness and that solved my problem.
 

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You're exactly right according to my research.

What I'm wondering is whether there's a device created to deal with this. Is there a relay with the stuff built in to let it behave in this scenario?

A diode is straight-forward but what sort of capacitor do I need and how do I add that in?

You'll have to play with the size of the cap a little but I would guess a 100u/16v electrolytic cap would be a good starting point. Connect it from where the diode connects at the relay.... and ground.
 

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Cut trigger wire going into relay. Add diode to prevent back feed. At the end of the where you would reconnect to the relay wire attach positive end of the capacitor and the relay trigger wire. The negative side of the capacitor can connect to any ground.

Alternatively if you are directly attaching the wires to the relay. You can feed the positive side of the capacitor into the connector for the trigger wire before you crimp it and the same for the ground.
 

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Discussion Starter #12
I'm not sure an ss relay would work. As per spec you need 3 to 32 v to make it work. Meanwhile I believe the jeep's PWM system dips down below the 3 volt mark. Quite possibly you would end up with a strobe effect.
That's interesting. Below 3V? How can the high beams run on this? Or are you saying it drops to below that between pulses and therefore the relay will be switching on and off rapidly just like the current mechanical one is doing, just without the noise?

This was what I expected my original solution would be. Some sort of relay that's made to handle the PWM on the input and produce a steady voltage on the output. Such a thing doesn't seem to exist though. At least not officially.
 

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That's interesting. Below 3V? How can the high beams run on this? Or are you saying it drops to below that between pulses and therefore the relay will be switching on and off rapidly just like the current mechanical one is doing, just without the noise?

This was what I expected my original solution would be. Some sort of relay that's made to handle the PWM on the input and produce a steady voltage on the output. Such a thing doesn't seem to exist though. At least not officially.

I haven't seen the actual jeep PWM lighting wave so I can't swear to it but usually a pwm wave fluctuates between 0 and max voltage. It does it really rapidly though so you can't see the blinking. If you have ever looked at an automotive led light through a cam (like your rear view cam) you can actually see it flickering off/on though. Because of the frame rate of the cam it can and does capture SOME of the on/off switching


Incandescent lighting in your house is similar only it operates on AC, which is ALTERNATING CURRENT. The reason they call it "alternating is because that's exactly what it does. It alternates between +max voltage and -max voltage at a rate of 60 times a second. In order to do that it has to cross the 0 volt line.... so in other words your incandescent light is actually turning on/off 60 times per second. Incandescent lighting however has a pretty slow decay rate so you can't see it flickering.
 

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Discussion Starter #14
I found a suggestion in another thread that offered the solution of telling the TIPM to change the PWM to use a full duty cycle instead of the 8v average it seems to be using now.

It might be a good solution if it's possible but I've never heard of any such thing being included in any programmers. Like, I've never heard of any indication that this is a configurable thing in the TIPM.

It seems to me that if it was, people would be talking about the "brighten your headlights" mod.
 

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I found a suggestion in another thread that offered the solution of telling the TIPM to change the PWM to use a full duty cycle instead of the 8v average it seems to be using now.

It might be a good solution if it's possible but I've never heard of any such thing being included in any programmers. Like, I've never heard of any indication that this is a configurable thing in the TIPM.

It seems to me that if it was, people would be talking about the "brighten your headlights" mod.

Absolutely. I've never tried it (I have the stock led lights) but apparently with Jscan you can reset the voltage to the lights to full.... or something to that effect anyway.
 

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Discussion Starter #16
Absolutely. I've never tried it (I have the stock led lights) but apparently with Jscan you can reset the voltage to the lights to full.... or something to that effect anyway.
Interesting. I've got JScan. I'll have to poke around in it and see if that can easily solve all my issues!
 

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Jscan may or may not work. I believe it is dependent on your year. But there are reports of it fixing the exact issue you described. (buzzing relay) I hope you have led headlights though as it might burn out stock lights at a faster rate.
 

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Discussion Starter #18
Yeah, I've got LED headlights now. :)

Hoping this works. I like when problems practically solve themselves. :)
 

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Discussion Starter #19
Well that was a bust. I found a setting for turning the factory LED headlight option on and off and I found settings for the left and right high beam "target voltage" that allowed a range from 13.0 to 13.8 with the factory set at 13.0.

I played with all those settings and accomplished nothing of value. At the higher settings, the relay actually buzzed worse and the lights started to flicker.

I'm back to square one. Put all the settings back to their original values and I guess I'll be playing with the wiring.
 

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I am not 100% sure on this as I dont have the proper instrument to verify. I think the jeep pwm for the lights might not be a rapid on off but rather fluctuating low to high voltage. If that is true you could try a solid state relay with a 3v trigger. I used one on my dome light to ground light setup. It ended up not allowing the fade effect to work as I would have needed one with a higher trigger voltage.
 
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