Weird headlight behavior

[Sharon]

I'm not sure how to even begin asking, so I'm relying on y'all to have had/heard some experience with this...

I had a low beam headlamp go out so I picked one up at Advanced Auto Parts. When the headlights are on the little lights (running? not intended to illuminate road?0 around the headlight assembly were flashing. Other side was fine. Yesterday, I went to change the lamp and it wasn't the right one. The replacement had about a 2" diameter base and the one I have on the truck looks like an old flash bulb (if you're old enough to remember those). Tiny little halogen plug in thing. The replacement is also halogen, no leds here. So, first question: are my headlight assemblies stock?

So, to continue to the really disturbing part... Without removing the old lamp I checked the voltage with a meter at the lamp. It too was flashing! Maybe the lamp isn't burnt out, but the flashing isn't applying enough voltage long enough to illuminate the lamp. Great! I had someplace else to be, so I reassembled the light to investigate it later.

Well, night came and I needed my lights to navigate narrow mountain roads. Fog lights work well so I turned them on. At one point, I hit the brights. The dash indicator lit up as expected, but my lights went out, except for the running lights! Total darkness. Lucky we had a decent moon. When I released the turn signal switch, the brights indicator went out and all my lights came back on except for the brights! So not even the brights would toggle and lock on/off as expected!

In the half minute or so I turned buttons and tried a few things so I'm not sure of the sequence, but I think I turned the headlights off completely and then hit the brights, the brights came on, release the switch and they went off. So I turn back on the rotary headlight switch... now my brights are stuck in the ON position! The indicator is on on the dash and everything else I tried would shut my lights off completely! I drove the rest of the way home with my brights on HOPING I didn't encounter any oncoming traffic because I had no place to pull off and turning off the lights would have been even worse! This is really dangerous and I need to get it resolved right away!

Are there relays somewhere? Does the computer control the lights? Any info on how these dang things work would be most appreciated? Links? Is my '04 basically the same for all 3rd gens? Maybe 4th/5th? Currently, "home" is a camper. The only internet I have is my phone. Electric is generated, water is hauled in. We're even too far out to receive any broadcast TV! I have some basic tools, probably enough to fix almost anything, but making repairs in a cow pasture is less than ideal.

I know it isn't much to go on, but I'm hoping someone will be able to "shed some light" on my problem. Thanks for all the help!

 

[Sharon]

Is this a factory headlight?

 

[Sharon]

Both low beam lights are now out. And the 6 small lights at the bottom of each headlight assembly now flash like a strobe light. The high beams and fog lamps (in the bumper) still work. If someone could explain the flashing, that would be a huge help.

 

[Sharon]

Okay... so I've discovered that these are some kind of "Spyder" "Sonar" headlight. Is this an aftermarket or some kind of OEM installed option at the factory or dealership?

 

[2016Bighorny]

110% aftermarket headlights...brand is: SPYDER 5009951

 

[Sharon]

Thanks. That's a start! Looks like these may have an HID option... or not, but I don't see any ballast anywhere and the lamp looks like a plain ole halogen. I stuck a meter on it and I am definitely getting fluctuating voltages at the same frequency of the flashing lower lights (leds, I'm guessing). So, that would indicate something in the Ram wiring is causing the flashing. Both low beam lamps look good.

 

[korby05]

I would honestly look on Amazon for a set of stock headlights like these. Plus make sure there aren't any changing to the wiring itself that could be causing your issues with lighting with the spyder lights installed. The can bus system doesn't like to be messed with.

Driver and Passenger Headlights Headlamps Replacement for Dodge Pickup Truck 55077121AF 55077120AG https://www.amazon.com/dp/B008G1ZX2K/ref=cm_sw_r_cp_apa_i_lzZ0BbA14Y1S9

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[WilliamS]

stock headlights would be brighter and better than those in every way. They look "cool" but do not throw light like a factory setup will. Or gut those pigs and do a retrofit with some quality parts.

 

[Sharon]

Great suggestion korby but I need to fix this now. It is my only transportation and I'm stuck in the middle of nowhere. I read that the "front module" under the distro box is often a problem.

 

[korby05]

Great suggestion korby but I need to fix this now. It is my only transportation and I'm stuck in the middle of nowhere. I read that the "front module" under the distro box is often a problem.

Front module? See I had problems recently with my rear taillights not working and I had to replace the whole fuse box. Luckily for me I was able to go to the junk yard and get one. O I understand completely because I'm in the same boat with it being my own transportation.

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[Sharon]

Seems like a lot of really "weird" lighting problems are related to the power distribution center pcb. Many people report their strange light problems go away after replacement. It will have to wait until another day. I hope the fog lights are sufficient to keep the cops off my back. I have a 60 mile trip to the airport I absolutely have to make tomorrow at 3:30 am. Ugh... gotta love stress! Thanks for the help, everyone!

 

[Sharon]

Korby, we cross-posted... yes, further reading confirms what you say about the fuse box. Some have reported that the FCM being disconnected and reconnected fixed it for a short time. Sounds like the connectors between the two were corroded for them. I may try just taking it apart and cleaning the terminals. I feel too vulnerable making big repairs far from home. I'd feel much more comfortable doing at my leisure in my own driveway.

 

[korby05]

Korby, we cross-posted... yes, further reading confirms what you say about the fuse box. Some have reported that the FCM being disconnected and reconnected fixed it for a short time. Sounds like the connectors between the two were corroded for them. I may try just taking it apart and cleaning the terminals. I feel too vulnerable making big repairs far from home. I'd feel much more comfortable doing at my leisure in my own driveway.

Haha. I agree. It seems to be a common problem with these trucks the older they get. Make sure to use some bulb grease on the connections after you're done.
My 02 has been great so far and on a plus side they are showing up in the junk yard so parts are pretty easy to get.

My issues with mine though is that it's the first year of the 3rd gen with the 5.9 magnum so I still have to cross back and forth sometimes with the 2nd gens and 3rd gens on some parts. The garage I go to even says they even have to go back as far as the build date to get the right parts.

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[Sharon]

Korby, after studying the schematic a little more, it looks like the headlights are controlled by the FCM and tail light relays are in the PDC. I'm afraid to take this thing apart as it will leave me stranded if anything gets hosed. I can receive packages but I'm kinda reliant on my truck to get fuel for the genny and propane for heat every few days.

On a side note, the high and low beams always seemed to be backwards to me. Are high beams on the inside or outside of the truck center line? I'm trying to consider if switching the wires from high beam (which work) terminals to the low beams'. I wouldn't have high beams but I don't usually need them with fog lights. My fear there is that if there is a circuit problem that caused the failure, by swapping the wires I may hose whatever module controls the high beams too.

 

[korby05]

Korby, after studying the schematic a little more, it looks like the headlights are controlled by the FCM and tail light relays are in the PDC. I'm afraid to take this thing apart as it will leave me stranded if anything gets hosed. I can receive packages but I'm kinda reliant on my truck to get fuel for the genny and propane for heat every few days.

On a side note, the high and low beams always seemed to be backwards to me. Are high beams on the inside or outside of the truck center line? I'm trying to consider if switching the wires from high beam (which work) terminals to the low beams'. I wouldn't have high beams but I don't usually need them with fog lights. My fear there is that if there is a circuit problem that caused the failure, by swapping the wires I may hose whatever module controls the high beams too.

So that would be the small silver box connected to the fuse box then. I mean I got the fuse box and the fcm together for less than $20 at the junk yard.

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[Sharon]

Well... a neighbor and I determined that the truck's circuitry was working (by disconnecting the halos and plugging in a standard headlamp). Great! So I began calling junkyards for replacement headlight assemblies looking for OEM ($750 for new is absurd). Remember, I'm out in the sticks and I need the assemblies immediately. I found them, one a half hour north, the other a half hour south. But, in talking to one of the junkyards, they said they could have "OE aftermarket" assemblies for me next day for about 80 bucks each. Had I not needed them that day, I would have gone that route. Anyway, as I'm on my way to the first junkyard, I'm passing by an O'Reilly's autoparts and thought, "What the heck, I'll just pull in and see if they had new replacements. It's a small Podunk town, but worth a shot. They said they could have them first thing in the morning. Still too late for me, but I asked if they were close enough to go pick them up myself. Luckily, they were only another 20 minutes down the road in another town. So, that's what I did. I paid the man for the lights and went to pick them up.

I replaced them in the parking lot as it was getting close to sunset. My headlights now work. It was the Halos all along. The new lights are cheap, but for $160 for the pair, I get to see while night driving and the lenses are clear. However, the new lights now reveal ANOTHER issue... More on that in <THIS> thread (to be added).