Installed LED Turn Signals - Brain Teaser
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=45124
Printed Date: May 17, 2025 at 6:46 PM
Topic: Installed LED Turn Signals - Brain Teaser
Posted By: calee4nyaboy
Subject: Installed LED Turn Signals - Brain Teaser
Date Posted: December 13, 2004 at 4:03 PM
Hey Everyone, I have a 2001 Chevy Blazer and I recently installed LED turn signal bulbs. Since the LED bulbs draw very little current, my factory electronic flasher (the 4 Prong pictured) now thinks that the bulb is burned out (or missing) so it flashes twice as fast giving me the "bulb out indicator" I was hoping an expert on flashers would be able to give me a hand.
I bought two variable load flashers (the 2 & 3 Prong pictured) at the auto parts store. These flashers are supposed to not care what the load is and flash the same no matter what kind of bulbs are present. Would anyone know how I could integrate these into my system so that my lights flash normal? I dont mind cutting some of the factory wires. I'm just not sure if I should completely remove my factory 4 Pronger or integrate the 2 or 3 Pronger into the system (with the 4 Pronger). I am also worried that I dont want my hazards or running lights affected by doing any of this.
Here are the flasher units (I colored in the letters yellow because they were kinda hard to read) From my understanding the "X" is "input" and the "L" is the load out to the lights. Not sure what the "P" is.
Replies:
Posted By: lesserblue
Date Posted: December 13, 2004 at 4:32 PM
Maybe a stupid question but did you buy the ones for Chevy's. Just because the are 3157's doesn't mean they will work. Take a look here (lightlen.com) for an example of what I'm talking about. If you did buy the right ones, I don't know what the problem might be.
Posted By: calee4nyaboy
Date Posted: December 13, 2004 at 4:52 PM
Yes, I bought the correct bulbs. This is not about a "problem". It's about putting a no load flasher in a system so that you can use any bulb you want with any load.
Posted By: lesserblue
Date Posted: December 13, 2004 at 5:24 PM
Check this site out. The sell "Load Resistor Kits". They may be able to tell you if that will fix your problem.
Posted By: calee4nyaboy
Date Posted: December 13, 2004 at 5:44 PM
No, no. Thats exactly what I dont want to do. Those load resisters do nothing but DRAW CURRENT acting as a regular bulb. I have moved to tiny current consuming LED bulbs so why move backwards and put resistors in there that draw what a normal bulb draws and get really hot. That very site says:
NOTES CONCERNING TAIL/SIGNAL/BRAKE LED BULBS
LED brake/tail lamps may not work with some thermal flasher units due to their extremely low current draw. These installations will require an electronic flasher unit, available at your auto parts store. Try to find flashers designed to work with LED bulbs, often HEAVY DUTY flashers will.
LED bulbs may cause some newer vehicles to indicate a bulb is burnt out (because of their low power consumption). Some cars indicate this by increasing the flash rate of the turn signals, some turn on a bad bulb indicator.This can be remedied with our Load Resistors wired across the turn signal bulbs to simulate a filament bulb load.
This site mentions exactly what I want to do: use a heavy duty flasher that doesn't care about the load it sees. It's a fairly easy hook up because there aren't many connections to a flasher. But I thought I'd ask someone that knew before I went fumbling around with this project...lol
Posted By: Hymer
Date Posted: December 13, 2004 at 7:04 PM
Hook it up to an external power supply and play with it...+12v -to gnd and one of the two prongs will flash.. it's the safest way, at least you'll just blow a flasher rather than messing with your truck off the bat..
Posted By: lesserblue
Date Posted: December 14, 2004 at 8:39 AM
calee4nyaboy wrote:
No, no. Thats exactly what I dont want to do. Those load resisters do nothing but DRAW CURRENT acting as a regular bulb. I have moved to tiny current consuming LED bulbs so why move backwards and put resistors in there that draw what a normal bulb draws and get really hot. That very site says:
NOTES CONCERNING TAIL/SIGNAL/BRAKE LED BULBS
LED brake/tail lamps may not work with some thermal flasher units due to their extremely low current draw. These installations will require an electronic flasher unit, available at your auto parts store. Try to find flashers designed to work with LED bulbs, often HEAVY DUTY flashers will.
LED bulbs may cause some newer vehicles to indicate a bulb is burnt out (because of their low power consumption). Some cars indicate this by increasing the flash rate of the turn signals, some turn on a bad bulb indicator.This can be remedied with our Load Resistors wired across the turn signal bulbs to simulate a filament bulb load.
This site mentions exactly what I want to do: use a heavy duty flasher that doesn't care about the load it sees. It's a fairly easy hook up because there aren't many connections to a flasher. But I thought I'd ask someone that knew before I went fumbling around with this project...lol
Yeah, I read that too. I didn't realize that your main concern was with the current draw (makes sense if you've got a LOT of audio/video stuff). Man!, I didn't realize you had to go through so much for LED bulbs. I was considering it but I may have to change my mind... who knows, I might have to wait on a pair of these. Sorry I couldn't help you and good luck with the flasher.
Posted By: calee4nyaboy
Date Posted: December 14, 2004 at 9:32 AM
Current draw is not my main concern. But after switching completely to LED bulbs, you are only moving backwards if you have to back and put regular bulbs and/or load resistors...totally defeats one of the main benefits of LED's.
This is not all that hard. All you have to do is change to a different flasher and it'll work. Im just not exactly sure on my particular vehicle what the pinouts would be. I've been playing with it so I have some idea but thought that SOMEBODY would know how on this forum. Adding some retarded standard bulbs or load resistors is easy but way lame.
Posted By: lesserblue
Date Posted: December 14, 2004 at 2:44 PM
From this website I found... "The X terminal is the +12V input, the P terminal output drives the flasher indicator in the instrument panel, and the L terminal drives the load (bulbs)." Also, the guys over here seem to be having similar issues. One guy suggests finding a replacement relay without the bulb out indicator. The discussion is pretty old so there might be other information elsewhere on the forums. Sorry I couldn't help more.
Posted By: naughtydog
Date Posted: December 14, 2004 at 5:53 PM
this guy sorted it
https://homepage.ntlworld.com/dgace/led_indicators.htm
Posted By: lesserblue
Date Posted: December 15, 2004 at 6:26 AM
great find dog.
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