JT2000WS6

I don't think this is the typical LED question that's been asked 1,000 times before... at least not from my searches have shown.

I replaced my DRL's up front with LED's but left the tail lights as the incandescent bulbs. I replaced the turn signal flasher with an EL12. I have not replaced the hazard flasher yet as I've read the stock unit can handle LED's and I rarely use the hazards so I figured I'd give the old unit a shot first.

The DRL function works just fine with the new LED's. However neither the turn signals nor the hazards work up front. They both flash just fine in the back and I'm not getting a quick flash on the dash as if a bulb was out.

Anyone have any idea why neither the turn signals nor hazards would not work only in the front after this mod?

Thanks again.

VIP1

Did you get the correct 3157 bulbs (they are dual filament)?

JT2000WS6

I double checked the description and it says they can be used as turn signals but doesn't specifically say they are dual function. Hopefully it's something as simple as that.

Thanks for bringing that possibility to my attention.

VIP1

A normal incandescent 3157 bulb has two filaments. One for high, one for low. So the LED equivalent must also be a 3157 replacement with a high and low function.

However, on a 1998-2002 Firebird, the High filament is used as both the Day Time DRL and the Turn Signal. The Low Filament is used as the Night Time DRL/Parking-Light. If I remember correctly.

So, with that thinking, if they are wired correctly, you should still have had a turn signal.

Unless you bought 3157CK which are wired differently. Actually, I'm not sure if they would even light up in a normal 3157 socket.

So test out that you have the correct bulb, try it in one of the tail light sockets. Don't put it in the housing (since and amber led behind a red lens is a waste, this is only for a test), just plug it into the socket. Turn on the parking lights and confirm that they work in low mode. Then press the brake pedal and have someone confirm that they brighten to high mode. If that works as expected, then they are the correct bulbs. In which case, something else is wrong with your font turn signals.

For another test, have you tried normal incandescent 3157 bulbs in the front and see if they still work correctly?

JT2000WS6

Everything worked normally as it should prior to the LED's but I haven't put the old bulbs back in to re-test.

The Guz

iTrader: (8)

Could you post a link to the bulbs you have so we can see what you have.

JT2000WS6

I swapped the bulbs to a pair that specifically said they were dual function and everything works just fine now. Looks like I learned a lesson in making assumptions about product descriptions.

VIP1

Were the other bulbs listed as 3157? If so, then they were marked wrong. Otherwise, when buying LED bulbs, buy the bulb with the same number as the bulb it replaces and get the color that matches the lens (or if the lens is clear, then get the correct color for the intended purpose).

WhiteBird00

iTrader: (4)

I've often wondered about that last part. It's common wisdom but I don't understand why. Why wouldn't you buy LED bulbs the same color as the incandescent bulbs they replace? Amber for the front obviously but you wouldn't buy red incandescent bulbs for taillights so why red LEDs? Especially since red LEDs don't produce nearly as much light as white ones for the same amount of power.

VIP1

Incandescent bulbs produce wide spectrum light.
LEDs produce narrow spectrum light.

A colored lens is a filter. A red lens only allows red light through. It doesn't convert the light.

Although a white LED produces a wider spectrum than a specific color LED (since it is white and white contains red as part of its visual specreum), it still isn't as wide as an incandescent bulb. A colored lens will block more of its light than an LED that matches the color of the lens.

However, as you noted, many white LEDs have a higher lumen rating than specific color LEDs, but much of that will be blocked by the lens. Also, due to that intensity, and automotive colored lenses aren't perfect, the net result may actually look a bit pinker with a white LED behind a red lens.

Optics also matter. Light source shape and placement changes in a housing greatly alter output.

8.Lug

I think you're under the impression that LED's draw more power. It's the complete opposite. The reason you use a heavy-duty flasher is simply because it doesn't change blink speed when the load changes - it will always blink the same rate if there's 100 bulbs attached to it or none at all.

8.Lug

White LED's are not actually white - they're blue, and there's a yellow coating over them to mimic white light. Notice the lack of red in that equation. Always use red LED's for red lights.

8.Lug

I notice lots and lots of these LED-related problem threads for the F-body. I'm curious if the problem is with how LED's work. LED's don't "turn on" until a specific voltage is reached called the "forward voltage" which is sometimes over 2 volts depending on the LED. Anything below that voltage is like the bulb is completely missing. I think this might actually be the real problem you've all been having. Try using load resistors on problem lights.

VIP1

It's a phosphor coating that glows white when excited by the blue led under it.

You are mixing scenarios here. Bare LEDs use between 2-4-ish volts depending on color and physical design. However, these automotive packaged replacement LED bulbs are configured to run typically in the 9-15v range (usually the sweet spot for their design is 12v). In this scenario you are discussing, the real issue is current, not voltage. LEDs draw much lower current. A "Load Resistor" increases current load in the circuit by wasting it as heat. Since the f-body has replaceable turn signal flashers, get Electronic "No Load" flashers to solve the turn signal issues. However, that won't solve the cruise control issue with the 3rd brake light being LED. The Tridon EL12 sometimes works for the flasher, but other brand No Load Electronic Flashers are better options that work more often.

8.Lug

I didn't say "phosphor coating" because it's a fairly pointless term in this scenario... and still doesn't change anything about what I said. White LED's are severely lacking in the red department unless you spend lots of money on hi-cri LED's which none besides professional photographers use.

And not sure what you're on about with the voltage ranges of these LED's because it's completely irrelevant. LED's don't "consume" voltage, they are simply diodes that require a certain voltage to activate the PN gate just like all diodes. Anything below that voltage and they will remain closed and act as insulators - and if the electronics in these cars use low-voltage to check if bulbs are blown or something else, this may be the reason why LED's wreak such havoc with the lighting systems in these cars.

I was simply trying to shed some light on the situation, but if you want to flex brain muscles - it's your move batman.

VIP1

You brought up voltage. While it is true that LEDs don't "consume" voltage like an incandescent bulb, it is also pointless to bring up the forward voltage of a single bare LED when these replacement bulbs are typically configured in series (and multiple of them depending on the total count of LEDs on the bulb) which would net an increased forward voltage for them to yield the desired output. The better bulbs also have more than just a resistor as well in its circuit, but that is also a different topic that would just further muddy this thread (the nicer bulbs will actually have a driver and bridge rectifier).

To my knowledge, cars with bulb-out indicators are usually checking current at normal voltage, not providing lower voltage "to see what happens" so to speak. If you have experience/schematics on this, please share.

Also, no need for condescending rhetoric. Lets be civil and helpful.

8.Lug

"To your knowledge" the car is using 12v like every other car, but obviously something is different here because I've never heard of a single other car that the cruise control stops working because you put in an LED 3rd brakelight. Or the rear directionals stopped functioning because you put LED DRL's in. Or name one of the other goofy problems that arise from using LED's in this chassis.

Clearly you don't know the answer - nor do I - which is why I was providing some insight into the unique functionality of LED's. Yet for some reason you're trying to undermine that while dismissing it altogether - all the while pretending to be some sort of LED engineer - and you're accusing ME of being condescending?

Look in the mirror dude.

And just so you know, I actually DO have an electronics background, and when talking to people that don't, I know not to use terms like "phosphor coating" or "bridge rectifier" because they're unnecessary and all they do is confuse the situation making it more difficult to explain something - all the while making you sound condescending.

Looks like you hit the mother-load.

WhiteBird00

iTrader: (4)

I've never heard of an f-body that experienced problems with the rear lights because of installation of LEDs in the front DRL / turn signals other than the inability of the original thermo-mechanical flasher to handle the reduced current flow properly. That causes all the signals to not flash (stay on solid) until either load resistors or an electronic flasher is installed.

The third brake light is a common problem in those f-bodies that don't come with LEDs there as standard equipment (like an SS does). But it certainly doesn't have anything to do with any system sending a low voltage signal through the light wiring.

And I agree with VIP1... a lot less attitude will get you much further in discussions here. Providing technical details is always welcome but condescending comments are not.

VIP1

Earlier in this thread I was trying to point out that the issue being exhibited is with current not voltage (especially in the case of the stock thermal flashers).

Turn signal problems are due to the stock thermal flashers that require a specific load to work properly. LEDs use lower current so they don"t heat up the metal strip in the flasher as much as incandescent bulbs.

As for the cruise control issue, it is suspected that the system checks that the car has functioning 3rd brake lights. There also, LEDs don't provide enough load to pass the test. Without dissecting the computer or speaking with an engineer that worked on it, we won't know for certain.

A car's voltage can swing from whatever the battery is at (often less than 12v if sitting for a while) to 14.5 at peak alternator output (typically).

I'm not undermining anything. You walked in with an attitude problem trying to refute and muddy things without actually helping. Have you read any of the previous threads on this topic? Have you tried to diagnose this before? Have you worked on other cars with similar issues and diagnosed the problem there? What were your findings? what was the solution? I've been on this forum since 2002 and have been through these LED threads many times (and on other forums). If you want more on lighting, check HID Planet.

If you have experience and information or diagnostic theories, please share and help.

As I said earlier, lets be civil and helpful.

Discussion and knowledge are appreciated, the "I'm better that you" attitude can find the exit.

thefirebirdman

<Original post removed>

I found this post which is my issue: https://ls1tech.com/forums/stereo-el...-not-work.html

Moving my questions to that thread.