Fog/High Beam Issue

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01RamSport318

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First off, this is my first time ever being in a forum, so if I am doing something wrong please inform me.

I have had bright yellow highs and lows for about a year now and my high beams just started messing up.
When I pull out the knob to cut on my fog lights, my high beams cut on as well. And at night I can see my high beam indicator barely light up. Also when I keep the fog lights off and just cut on my high beams, the lows shut off, then if I pull the fogs on, the fogs and lows cut on.
Has anyone encountered this or does anyone have any ideas to what is going on?
Thanks for any help.
 

R.L.K.

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Well , your not doing anything wrong . You posted a Heading that briefly describes your issue and you posted in the correct area .
Welcome to the Ram Forum Sir glad to have you here !
Read lots post lots and help others when you can .

As for your issue , have you owned this truck since new ?

Have you installed an aftermarket harness for high beams with fog light operations?

If your trucks lighting system is 100% OEM then I'd be looking for a lighting module or a relay ?

Hope this helps !
 

dudeman2009

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I'm putting this out there because mine did this too. Since you have aftermarket lights, im going to guess its got electronic ballasts if its got this problem. Most all Aftermarket LED or HID drivers will run full bridge rectifiers on the input to work with positive and negative ground systems.

Before you read further, the low beams are supposed to shut off when you turn on the high beams. On incandescent bulbs if it didn't, there would be increased wear on the filaments from the increased heat production of long term high beam usage.

The lows coming on with the fogs however, is not supposed to happen.

What has likely happened is one of the drivers has failed and is sourcing ground through the fog lamp relay. Do you have sport model and or DRL?

The easy fix is to go get a power resistor (preferably wire wound) and put it in parallel with the high beam plug. I cant remember the exact resistance needed, I calculated it out one time to fix this same problem on my truck, but I never got around to it.

Our trucks are positive ground on the front lighting system, everything is backwards. Only experienced techs, techs who've been trained on positive ground systems, and people who have a knack for electrical can quickly and easily solve these problems. Normal guys can as well, but it is more difficult for them.

Try this. Turn on your low beams and fogs. You high beams should also come on. Unplug one of your headlights and see if the highs turn off, if not, try the other headlight. That is the easiest way to rule out which light is malfunctioning.

Sorry if I cant be of much help, over the internet diagnostics of the front lighting system is kind of difficult.
 
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01RamSport318

01RamSport318

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I have not had the truck since new. I have had it for about 5 years though. The same lights have been in the truck for about 3 years now. All the lights are OEM. They are regular bulbs that have a deep yellow tint on them which makes them yellow. They are not HID or LED. I can't look back to see if I mentioned this but at night when I cut on the fog lights and the brights cut on with them, there is about a 2 second delay before the brights cut on. And sometimes the brights won't come on at all, but when I just flash my brights, they stay on when the fogs are engaged. Either way, (only when it is dark outside) the bright light indicator comes on very slightly when the fogs are on. The indicator works normal when I am not using the fogs at all. For the past 4.5 years the lights have worked great, and the dims would stay on when I cut the brights on. And now if I have the fogs off and cut the brights on, the dims go out. It happened out of the blue, after watching a movie at the drive in theater. I looked for a ground wire but have no clue where one could be. Does anyone know if it could just be a bad ground? And if so, do you know where one might be located? Sorry this is so long, it is just a very confusing scenario to me and don't know how else to explain it.
 

R.L.K.

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Daytime Running Lights
 
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01RamSport318

01RamSport318

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Oh ha, nope, but that reminded me, when I just have the running lights on and cut on the fogs, the highs still cut on as well... even with the headlight switch not turned to on.
 

dapepper9

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Highly possible the high amperage of the factory lights (especially the sport quads) melted the inner part of the switch. Very common issue. Id start with a switch replacement and probably add a relay to take the load off
 
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