calling all lighting geniuses...
Thread Starter
Drifting
Joined: Dec 2010
Posts: 1,254
Likes: 7
From: Columbus Oh
need switchback led lighting help please
I am trying to wire up a switchback led strip in my front corner lights. My end goal is to have my 3157 bulb be on all the time and not function as a turn signal, and have the switchback led strip act as the drl and turn signal. right now i have the switchback led strip tapped into the brown and black wires from the 3157 socket and wired to the blue wire. the blue wire is not connected to the 3157 socket anymore. it all seems to be working ok except that when just the drl is on, all the interior and exterior lights start flashing super fast. if i turn on the parking lights or headlights everything acts as it should. what did i do wrong?
thanks,
dave
thanks,
dave
Last edited by 02z06dave; Mar 20, 2012 at 06:29 AM.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Your thread title nearly put me off
Radioflyer is the real guru on lighting mods but we might be able to work this out.
I had to modify my lights to comply with local safety standards when I brought my car home to UK. What I needed was a dedicated turn signal using the existing 3157. The difference from what you want is that amber DRLs and amber parking lights are illegal here so I inhibited my DRLs. My modified parking lights are wired into my T85 headlights. My mod is therefore similar in concept (apart from you using LEDs) but mine works fine.
As you know, on a stock car, the dual filament 3157 bulb and holder provides turn signals, parking lights and DRLs. There are 3 wires running to the bulbholder:
a blue/white wire which is the hot feed for the turn signals.
a brown wire which is the hot feed for the parking lights.
a black wire which is the common ground.
I cut the brown wire to disable the orange parking light on the 3157 leaving a dedicated turn signal. What I never worked out, because it wasn’t relevant to me, is where the DRL is fed into the circuit. What I do know is that the DRL still operated until I pulled the A2 fuse ( and eventually did the relay mod) even with the brown wire cut. That means the DRL signal is fed into both the parking light and the turn signal circuits somewhere upstream of the turn signal bulb. It feeds onto both the blue and the brown circuits.
Turning to your problem.
I’d say you’re correct in your logic. Cutting the blue and leaving the brown should give just amber parking lights at the 3157. Using the blue for the new LED should give turn signals at the LED. If my logic is correct, the DRLs should still operate on both circuits in the way you have it configured. When you manually select the headlights, the DRLs will go off and the system works as you want it to. So far so good.
I’m no LED expert but the hyperflash is normally because the sensing system sees the LEDs as a failed bulb. Others may comment but I think you need a ballast to fool the system into thinking it still has a 3157 on the blue turn signal circuit. I guess you could actually just wire in a redundant 3157 to achieve the same thing.
Try pulling the A2 fuse to disable the DRLs. Check to see if the lights then work normally (twilight sentinel on and off and when selected manually). From what you say, they should. That means the problem is definitely on the DRL side. I would get a ballast from one of the LED vendors, wire it in on the LED side and see what I had at that point. Hopefully if the system thinks the LED is a normal bulb it will not flash.
Let us know how you go.
Radioflyer is the real guru on lighting mods but we might be able to work this out.
I had to modify my lights to comply with local safety standards when I brought my car home to UK. What I needed was a dedicated turn signal using the existing 3157. The difference from what you want is that amber DRLs and amber parking lights are illegal here so I inhibited my DRLs. My modified parking lights are wired into my T85 headlights. My mod is therefore similar in concept (apart from you using LEDs) but mine works fine.
As you know, on a stock car, the dual filament 3157 bulb and holder provides turn signals, parking lights and DRLs. There are 3 wires running to the bulbholder:
a blue/white wire which is the hot feed for the turn signals.
a brown wire which is the hot feed for the parking lights.
a black wire which is the common ground.
I cut the brown wire to disable the orange parking light on the 3157 leaving a dedicated turn signal. What I never worked out, because it wasn’t relevant to me, is where the DRL is fed into the circuit. What I do know is that the DRL still operated until I pulled the A2 fuse ( and eventually did the relay mod) even with the brown wire cut. That means the DRL signal is fed into both the parking light and the turn signal circuits somewhere upstream of the turn signal bulb. It feeds onto both the blue and the brown circuits.
Turning to your problem.
I’d say you’re correct in your logic. Cutting the blue and leaving the brown should give just amber parking lights at the 3157. Using the blue for the new LED should give turn signals at the LED. If my logic is correct, the DRLs should still operate on both circuits in the way you have it configured. When you manually select the headlights, the DRLs will go off and the system works as you want it to. So far so good.
I’m no LED expert but the hyperflash is normally because the sensing system sees the LEDs as a failed bulb. Others may comment but I think you need a ballast to fool the system into thinking it still has a 3157 on the blue turn signal circuit. I guess you could actually just wire in a redundant 3157 to achieve the same thing.
Try pulling the A2 fuse to disable the DRLs. Check to see if the lights then work normally (twilight sentinel on and off and when selected manually). From what you say, they should. That means the problem is definitely on the DRL side. I would get a ballast from one of the LED vendors, wire it in on the LED side and see what I had at that point. Hopefully if the system thinks the LED is a normal bulb it will not flash.
Let us know how you go.
Last edited by DeeGee; Mar 20, 2012 at 04:56 AM.
Thread Starter
Drifting
Joined: Dec 2010
Posts: 1,254
Likes: 7
From: Columbus Oh
Your thread title nearly put me off
Radioflyer is the real guru on lighting mods but we might be able to work this out.
I had to modify my lights to comply with local safety standards when I brought my car home to UK. What I needed was a dedicated turn signal using the existing 3157. The difference from what you want is that amber DRLs and amber parking lights are illegal here so I inhibited my DRLs. My modified parking lights are wired into my T85 headlights. My mod is therefore similar in concept (apart from you using LEDs) but mine works fine.
As you know, on a stock car, the dual filament 3157 bulb and holder provides turn signals, parking lights and DRLs. There are 3 wires running to the bulbholder:
a blue/white wire which is the hot feed for the turn signals.
a brown wire which is the hot feed for the parking lights.
a black wire which is the common ground.
I cut the brown wire to disable the orange parking light on the 3157 leaving a dedicated turn signal. What I never worked out, because it wasn’t relevant to me, is where the DRL is fed into the circuit. What I do know is that the DRL still operated until I pulled the A2 fuse ( and eventually did the relay mod) even with the brown wire cut. That means the DRL signal is fed into both the parking light and the turn signal circuits somewhere upstream of the turn signal bulb. It feeds onto both the blue and the brown circuits.
Turning to your problem.
I’d say you’re correct in your logic. Cutting the blue and leaving the brown should give just amber parking lights at the 3157. Using the blue for the new LED should give turn signals at the LED. If my logic is correct, the DRLs should still operate on both circuits in the way you have it configured. When you manually select the headlights, the DRLs will go off and the system works as you want it to. So far so good.
I’m no LED expert but the hyperflash is normally because the sensing system sees the LEDs as a failed bulb. Others may comment but I think you need a ballast to fool the system into thinking it still has a 3157 on the blue turn signal circuit. I guess you could actually just wire in a redundant 3157 to achieve the same thing.
Try pulling the A2 fuse to disable the DRLs. Check to see if the lights then work normally (twilight sentinel on and off and when selected manually). From what you say, they should. That means the problem is definitely on the DRL side. I would get a ballast from one of the LED vendors, wire it in on the LED side and see what I had at that point. Hopefully if the system thinks the LED is a normal bulb it will not flash.
Let us know how you go.
Radioflyer is the real guru on lighting mods but we might be able to work this out.
I had to modify my lights to comply with local safety standards when I brought my car home to UK. What I needed was a dedicated turn signal using the existing 3157. The difference from what you want is that amber DRLs and amber parking lights are illegal here so I inhibited my DRLs. My modified parking lights are wired into my T85 headlights. My mod is therefore similar in concept (apart from you using LEDs) but mine works fine.
As you know, on a stock car, the dual filament 3157 bulb and holder provides turn signals, parking lights and DRLs. There are 3 wires running to the bulbholder:
a blue/white wire which is the hot feed for the turn signals.
a brown wire which is the hot feed for the parking lights.
a black wire which is the common ground.
I cut the brown wire to disable the orange parking light on the 3157 leaving a dedicated turn signal. What I never worked out, because it wasn’t relevant to me, is where the DRL is fed into the circuit. What I do know is that the DRL still operated until I pulled the A2 fuse ( and eventually did the relay mod) even with the brown wire cut. That means the DRL signal is fed into both the parking light and the turn signal circuits somewhere upstream of the turn signal bulb. It feeds onto both the blue and the brown circuits.
Turning to your problem.
I’d say you’re correct in your logic. Cutting the blue and leaving the brown should give just amber parking lights at the 3157. Using the blue for the new LED should give turn signals at the LED. If my logic is correct, the DRLs should still operate on both circuits in the way you have it configured. When you manually select the headlights, the DRLs will go off and the system works as you want it to. So far so good.
I’m no LED expert but the hyperflash is normally because the sensing system sees the LEDs as a failed bulb. Others may comment but I think you need a ballast to fool the system into thinking it still has a 3157 on the blue turn signal circuit. I guess you could actually just wire in a redundant 3157 to achieve the same thing.
Try pulling the A2 fuse to disable the DRLs. Check to see if the lights then work normally (twilight sentinel on and off and when selected manually). From what you say, they should. That means the problem is definitely on the DRL side. I would get a ballast from one of the LED vendors, wire it in on the LED side and see what I had at that point. Hopefully if the system thinks the LED is a normal bulb it will not flash.
Let us know how you go.
thanks for the help
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
are you thinking i should wire a load resistor in? I think having the hyper flash harness eliminates the need for that which i have already. I should have said that in my original post. perhaps i still need a resistor though or maybe a diode. looks like a trip to radio shack is in my future.
thanks for the help
thanks for the help
It still seems logical that this is the problem
Last edited by DeeGee; Mar 20, 2012 at 07:18 AM.
Thread Starter
Drifting
Joined: Dec 2010
Posts: 1,254
Likes: 7
From: Columbus Oh
No trouble. I would have thought a hyperflash harness would work so we may be on the wrong track. Why not wire a spare 3157 bulbholder in series on the LED side of the circuit. That way you can eliminate the lack of a normal bulb as a cause. If it is the issue, you can then fit the correct load as a permanent fix.
It still seems logical that this is the problem
It still seems logical that this is the problem
Supporting Vendor
Joined: Jul 2010
Posts: 8,548
Likes: 900
From: Republic of Texas
To do what you're trying to do is a little more complicated solution since the Turn signal and DRL circuit use the same wires from the fuse-box to the bulb.
You would need to find where the turn signal wires come out of the BCM to the front signals (before the DRL circuit is involved if possible), cut that wire and run it to the switchback LED strip. Then ensure the DRL is functioning. If not there is a DRL relay circuit in the passenger foot-well fuse box. You'll need to rnu a second set of wires to your DRL bulb from there. The parking lights should be much easier allowing you to tap power from the 194 marker bulb or the low power on the 3157 bulb.
You would need to find where the turn signal wires come out of the BCM to the front signals (before the DRL circuit is involved if possible), cut that wire and run it to the switchback LED strip. Then ensure the DRL is functioning. If not there is a DRL relay circuit in the passenger foot-well fuse box. You'll need to rnu a second set of wires to your DRL bulb from there. The parking lights should be much easier allowing you to tap power from the 194 marker bulb or the low power on the 3157 bulb.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Drifting
Joined: Dec 2010
Posts: 1,254
Likes: 7
From: Columbus Oh
To do what you're trying to do is a little more complicated solution since the Turn signal and DRL circuit use the same wires from the fuse-box to the bulb.
You would need to find where the turn signal wires come out of the BCM to the front signals (before the DRL circuit is involved if possible), cut that wire and run it to the switchback LED strip. Then ensure the DRL is functioning. If not there is a DRL relay circuit in the passenger foot-well fuse box. You'll need to rnu a second set of wires to your DRL bulb from there. The parking lights should be much easier allowing you to tap power from the 194 marker bulb or the low power on the 3157 bulb.
You would need to find where the turn signal wires come out of the BCM to the front signals (before the DRL circuit is involved if possible), cut that wire and run it to the switchback LED strip. Then ensure the DRL is functioning. If not there is a DRL relay circuit in the passenger foot-well fuse box. You'll need to rnu a second set of wires to your DRL bulb from there. The parking lights should be much easier allowing you to tap power from the 194 marker bulb or the low power on the 3157 bulb.
Thanks,
Dave
Thread Starter
Drifting
Joined: Dec 2010
Posts: 1,254
Likes: 7
From: Columbus Oh
To do what you're trying to do is a little more complicated solution since the Turn signal and DRL circuit use the same wires from the fuse-box to the bulb.
You would need to find where the turn signal wires come out of the BCM to the front signals (before the DRL circuit is involved if possible), cut that wire and run it to the switchback LED strip. Then ensure the DRL is functioning. If not there is a DRL relay circuit in the passenger foot-well fuse box. You'll need to rnu a second set of wires to your DRL bulb from there. The parking lights should be much easier allowing you to tap power from the 194 marker bulb or the low power on the 3157 bulb.
You would need to find where the turn signal wires come out of the BCM to the front signals (before the DRL circuit is involved if possible), cut that wire and run it to the switchback LED strip. Then ensure the DRL is functioning. If not there is a DRL relay circuit in the passenger foot-well fuse box. You'll need to rnu a second set of wires to your DRL bulb from there. The parking lights should be much easier allowing you to tap power from the 194 marker bulb or the low power on the 3157 bulb.
thanks
Supporting Vendor
Joined: Jul 2010
Posts: 8,548
Likes: 900
From: Republic of Texas
