How to Install Load Resistors for LED Turn Signal Lights

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Introduction: How to Install Load Resistors for LED Turn Signal Lights

About: Everything about automotive LED lights

Why are installing load resistors necessary for LED turn signal lights? If you don't install load resistors (also known as equalizers) with LED turn signal bulbs, you will experience the notorious hyper flash issue. Hyper flash is exactly what it sounds like, where the turn signal light flashes rapidly and is almost headache inducing. Not only is this ugly, but you may also attract the police who think your bulb is burned out. This sounds completely unnecessary and a huge hassle to boot.

You will need 50W 6 OHM load resistors and tap the load resistor to the stock harness in parallel. Load resistors also have no negative or positive, making it easier for you because you wouldn't have to worry about which wires goes to which side.

Step 1:

1156, 3156, 7440 are single filament applications so there are only two wires (one positive, one negative). This is very straightforward as you need to simply tap the load resistor wires between the two wires.

Step 2:

1157, 3157, and 7443 are double filament applications which have three wires (one shared negative, one positive dim mode, and one positive brighter/blinker mode.) There is a little more trial and error involved with the wiring. We recommend you tap the load resistor between the most vivid wire color (usually the brighter/blinker) and the least wire color (usually negative). In this tutorial, we are going to try to tap the resistor the red and black wires.

Step 3:

Test the turn after the wires are tapped. If the turn signal still hyper flashes, take the wires out and tap it to another wire and try again. The most times you will try to tap the wires is three times. We are going to assign each wire with a letter for easier reference: Red-A, Green-B, and Black-C. We originally tried A and C and tested it to see if it works. If not, try and C. If that still doesn't work, try A and B.

Step 4:

If you have tried all three ways and the hyper flash issue is still there, then perhaps the issue causing this is the connection. Many people install load resistors with a T-tap because it sounds easy, but we definitely don't recommend this route. T-taps are sometimes unable to cut through wire and causes a loose connection or intermittent function. We recommend you directly merge the load resistor to the stock harness. Actually, my professional stereo installations have installers merge the wires instead of using T-taps.

Step 5:

How to merge the wires: We recommend you use a wire stripper to expose the copper wire in a small slit without damaging anything. If you don't have a wire stripper, you can also scrape through the plastic using a knife or scissors. Don't forget to use electrical tape to cover it after you connect the wires. An awesome thing about merging wires is that they have a 100% success rate every time. You won't have that intermittent working/not working issue like the T-taps. Don't forget to mount the load resistor to the metal using zip-ties and not double-tape.

Step 6:

Summary:

1. Merge wire instead of using T-taps for a perfect connection.

2. Always try different wire combinations for double-filament bulbs.

3. Mount the resistor to metal so you can prevent heat damage.

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    118 Comments

    0
    JosephC337
    JosephC337

    Question 2 days ago

    I have a 1979 Cb750f and I changed to LEDs. Originally it all worked, but soon after I get the 4 way static light if I turn one way and nothing if I the other.

    I have LEDs at all lights and in the instrument panel

    Any ideas?

    0
    viruz1124
    viruz1124

    Question 7 months ago

    My front tune signals are 7444 leds. There flashing normal but the dash is blinking fast and I got error message on dashboard “turn signals out”! 2017 grand Jeep Cherokee limited.

    Question can I install the resistor on the rear turn signal that carries factory halogen bulbs or do I need to install the led resistor on the front turn signal that have the leds?

    9684096C-9FC6-4454-965A-870F35F2F830.jpeg
    0
    Wo1fMane
    Wo1fMane

    3 years ago

    OEM flashers work by sensing the current draw, and if the current draw is much less than the factory setup it assumes that a bulb is out and flashes very rapidly in order to alert the driver that a bulb is out. LEDs draw a lot less current (and therefore power) than the equivalent incandescent bulbs, so the OEM flashers don't recognise them and act as if a bulb is out. Load resistors work by deliberately wasting power by converting it directly to heat rather than light. If that sounds dumb, it is. Load resistors should be your very last resort if you can't find a replacement LED flasher that will work with your vehicle. A replacement flasher has the added benefit of being plug-and-play, requiring no modification whatsoever to your vehicle or its wiring.

    Don't use a 50 watt resistor just because some guy on the Internet tells you to. It's overkill and wastes power, not to mention creating a lot more heat than necessary in many situations. Look in your vehicle's owner's manual (or on the existing incandescent bulb if it's readable) and use the wattage of the existing lamps or maybe even slightly less.

    Also, if you're doing a permanent install never just "merge" the wires as described above. They will corrode, even if you cover them with electrical tape, and eventually the connection will degrade. Always solder the wires.

    I have two motorcycles; one is 100% electric and the other is an ICE bike that is known to have a weak electrical system.

    I have converted the electric bike to all LEDs in order to save energy and maximize range. I replaced the flasher on it and it works like a charm.

    Unfortunately, the ICE bike for some reason doesn't work with the flasher that according to the schematics and pinout should work. Using load resistors completely defeats the purpose of using LEDs because it just uses the same (or in the case of a 50 watt resistor, WAY MORE!!!!!) power than the original bulbs. However, I did find that 6 watt resistors work (as opposed to the original 10 watt bulbs) and still save a couple of watts over stock. Not ideal, but it works as a stop-gap until I can figure out why the flasher replacement doesn't work.

    0
    Wo1fMane
    Wo1fMane

    Reply 3 years ago

    P.S. Your headlight bulbs are 55 or 60 watts. If you use a 50 watt resistor you're turning the same amount of energy directly into heat that your headlights turn into light. And have you ever touched a lit headlight bulb? (DON'T!!!) They already waste a lot of energy as heat. With sealed beams they're just hot, but with halogens you'll instantly get burned. (You don't want to directly touch halogen bulbs even when they are cold because the oil from your fingers will make the bulb break when it heats up. Use gloves or a clean rag to handle and install them.)

    Don't use 50 watt resistors unless it's specifically called for in your application.

    1
    gilligan8
    gilligan8

    Reply 1 year ago

    But the wattage of your bulb is how much power it will DRAW.

    The wattage of a resistor is how much power it can handle.

    These are VERY different.

    The OHM is what determines how much power the resistor will "see" through it. No matter what wattage resistor you have, it will see the same power. If it's underrated then it will burn up.

    Put a 1/4 watt 6 ohm resistor across your battery and watch it burn up in smoke. This is why you need a larger wattage resistor to handle the power that will go through it based on the resistance.

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    You're wrong, and completely missing the point. The point is that you need those high power resistors BECAUSE THEY ARE GOING TO DRAW A LOT OF POWER. If a small resistor would do, then you're drawing a small amount of power and it's no big deal. But the fact is, you HAVE to use those big resistors because they WILL draw nearly that much power, and then dissipate it as heat. It is hugely wasteful (and sometimes dangerous, because those resistors can get VERY hot) and defeats most of the benefit of using LED lamps.

    0
    gilligan8
    gilligan8

    Reply 1 year ago

    But wait, then how am I wrong? That's exactly what I am saying.

    You NEED the high power resistor because the circuit will draw a lot of power (it's Ohms Law).

    yes, it's wasteful and it produces a fair amount of heat... and maybe it's the the best way to "fix this"... but it's not incorrect.

    For your E-Bike it's a terrible plan because like you said, it's wasteful. For an ICE then it doesn't really matter that much.

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    You're still wrong. All bikes have a relatively tiny "alternator" and will benefit from power savings, especially if you start adding accessories like auxiliary lights, heated grips or phone chargers. A lot of ICE bikes have problematic electrical systems from the factory, and every little bit helps. Conversely, adding more current draw back in with load resistors is a bad idea.

    0
    gilligan8
    gilligan8

    Reply 1 year ago

    You seem to like to tell people they are wrong a lot.

    This instructables was started about cars. You brought your bike into the fray.

    Either way, Ohms Law is Ohms Law... I don't know why you are so determined to be right and someone else be wrong.

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    There's the pot calling the kettle black. I made a comment, and you are the one who said I was wrong. I'm just giving examples why that's not the case. As for bike vs. car, it's just a handy example. I also have a car that has the flasher circuit built into the ECU, which means there's no possibility of replacing the flasher. I still want to use LEDs, but I am *NOT* going to use load resistors, because for all the facts I keep repeating it's a dumb idea. I will find another way that doesn't waste power or risk fire.

    1
    NightFire
    NightFire

    Reply 1 year ago

    This has been a painful read, I'm not going to get in to the resistor argument here.

    What I will say is that you should avoid soldering wires on vehicles, proper crimping is the appropriate way to make connections (using a decent crimp tool) on a vehicle.

    Look at any factory wiring harness, on any form of transportation, they are crimped. Aircraft are forbidden to ever have soldered connections, and are inspected for them.

    Crimping isn't done because it's faster and easier (it is). It's done, because metal fatigue causes soldered joints and wires to regularly fail in vehicles

    I'm a retired avionics engineer dealing specifically with military aircraft, it was my job to make sure my aircraft electronics systems wouldn't fail

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    Talk about painful read...
    1. Aircraft are subject to entirely different conditions and environments than anything else, and what works for aircraft is not appropriate for cars or especially motorcycles and vice versa.
    2. Crimping is done for two reasons, and two reasons only: it's quick and it's cheap.
    3. Crimping is *NOT* any better for metal fatigue. That is patently false. If a wire is held rigidly on one end and flaps around on the other, it's utterly irrelevant whether it is crimped or soldered, it will eventually fail regardless. Adding strain relief will help, but the correct solution is to properly route and support wires so they don't flop around.
    4. Aircraft don't have to deal with all the road chemicals that surface vehicles do and components are for the most part enclosed, out of the elements. Motorcycle components in particular are completely exposed to the elements.
    5. Very few people have decent crimping tools. The ones available at auto parts stores are utter crap and are impossible to make a proper crimp with. In fact, I have yet to find a store of any kind that sells a decent crimper. I don't know where the tradesmen get theirs.
    6. The DIY tendency these days is to use those abominable wire taps that cut through the insulation and are easy to install with just a pair of pliers. Those in particular are unreliable and asking for trouble.
    7. I have lost count of how many factory crimped connections I've had to replace over the years because they have corroded. And many have failed mechanically because there was no strain relief or proper support. I have yet to see a good soldered connection fail for any reason. So yeah, I've looked at them and no, they're not better.

    0
    NightFire
    NightFire

    Reply 1 year ago

    A lot of your points are valid, but some are only partially true.

    Yes, aircraft do experience vastly different environments, but those environments are far more harsh than road travel, including exposure to chemicals and environmental extremes. Not too many road bound vehicles are subjected to jet fuel or hydraulic fluid most days they operate, while operating at extreme pressure and temp variations within minutes.

    Aircraft range from low altitude single seat prop planes, to passenger jets, to super sonic high altitude recon planes to cargo helicopters to attack helicopter to transport. They all have the same types of connections, as do all production vehicles. Even trains and ships crimp instead of solder. If you've never been in a Chinook, you have no idea the amount of chemicals those things spray all over everything, and every military helicopter will vibrate teeth loose.

    Aircraft components are usually in their own bay, but those bays aren't sealed. I've pulled gyroscopes out of every type of aircraft I worked on that would be covered in some type of corrosive solution.

    The only industry I know of that chooses solder over crimping is the space industry, but those are far different circumstances than anyone else would experience.

    Crimping IS quick and cheap, for someone doing a specific connection once. Manufacturers have robots that do the crimping, those robots could just as easily solder, and soldering would be much cheaper and just as fast. Solder is far cheaper than crimp connectors. On some connections, they probably wouldn't even use solder, probably just a tack weld, like they do to other parts of cars

    A ratcheting crimp tool is easy to find, you can get a Klein for $25

    A proper crimp joint will create a homogeneous piece of copper, there won't be any air gaps in it. Soldering fills in the gaps between copper with tin and lead (or tin and silver), creating a bond of dissimilar metals and an area ripe for galvanic corrosion, which is nearly impossible to avoid on the outside of a vehicle, it's difficult to avoid inside a sealed compartment.

    You seem to be too busy feeling like you're being personally attacked and trying to justify doing things your way, you're not willing to see people are simply trying to offer more information.

    Understand, I have a Master's Degree in Electronics Engineering, and specialized in avionics. Just because I choose to specialize in a certain field doesn't mean I don't still know all of the other things I learned. You seem to think that you're common opinion on soldering wires is superior to my ~40 years worth of training and experience

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    Jet fuel is *not* corrosive. It weakens natural rubber (as does alcohol, which is the one and only reason that old vehicles shouldn't be filled with ethanol without a thorough refit of all hoses and rubber parts; it WILL NOT HURT THE ENGINE), because it is a *solvent*, not corrosive, and doesn't affect most metals. Fuels and hydraulic fluids are also toxic and really bad for bare skin, but again that's not the same thing as corrosive. The same goes for hydraulic fluid. What *is* corrosive is road salt and every other ice- and snow-melt compound, which aircraft do *not* have to deal with. (The exception is amphibious aircraft that work on and around the ocean, but that's another whole batch of issues.) And gunk or stain isn't corrosion. You need to go look up the word "corrosive".

    Aircraft in general are much more prone to vibration because the powerplants are much more rigidly mounted than in surface vehicles and the way the whole structure is constructed is more prone to transmitting vibrations. Hence the "safety wire" all over the place which you will only find on race cars, never consumer surface vehicles.

    Soldering is NOT cheaper or faster than crimping, especially for automated lines. Soldering requires some time, however short, to heat up *all* the parts to prevent "cold solder" joints, which sometimes don't work at all and will always fail in short order. Then the parts have to cool down so the solder can set (and cooling or heating too quickly causes problems as well) before they can be moved, which further slows down the line. Crimping, on the other hand, can be done in a tiny fraction of the time and the usual crimp alloys are cheaper and easier to produce than solder.

    A proper crimp makes a good joint, and it may make a "homogenous piece of copper" if both the wires and crimp are copper, but that's usually not the case. In fact, the crimp is usually of a different material and causes exactly the galvanic corrosion that you ascribe to solder. Then the exposure to actual corrosive chemicals compounds the issue.

    I have technical degrees as well, and I'm very familiar with chemistry and physics. But degrees don't mean anything if you don't actually understand the material, which you clearly don't. I have just as much experience as you, but unlike you I understand why things are done they way they are and why employees are told things that aren't true in order to keep them from thinking for themselves. Like that old nugget about metal fatigue. If a crimp makes a "homogeneous mass" as you say, then there is obviously zero difference between a crimp and solder because both are a solid, large cross section which is subject to identical tensile stress along the outside edge when subjected to a bending force. Which is why wires that are subject to bending are many small strands instead of one big one; the small strands have much smaller stresses for the same bending angle and can withstand repeated bending much, much longer. If you try to bend a solid core wire and an otherwise identical (material type and diameter) multi-strand wire the solid core will be very stiff but the multi-strand will still be quite flexible. But if your "proper crimp joint" makes it all one homogeneous strand, that's out the window. Ergo, the metal fatigue assertion is pure baloney because the truth is that nobody wants to explain that soldering would be much better but they're never going to do it because it's much, much slower and much, much more expensive.

    And yes, I get miffed when people "offer" misinformation and claim to know things they don't.

    0
    NightFire
    NightFire

    Reply 1 year ago

    You're trying to find reasons to argue and specifically attack my knowledge and experience.

    I never stated jet fuel or hydraulic fluid were corrosive to wires, I simply used the 2 most obvious fluids to demonstrate that aircraft are not operating in some sterile environment, which you seem to think they are.

    Aircraft are not even relative to the conversation, you're the one that brought them into the conversation in an attempt to disqualify my 4 decades of experience as an engineer, I only brought them up in reply to your comments.

    I made 2 statements about corrosion, 1 was that aircraft are subjected to corrosive fluid and 2 was about galvanic corrosion.

    Machines are not restricted to the soldering techniques that people are, there are a lot of options for mass production soldering that's very fast.

    I did fail to mention previously, most crimp connectors have built in stress relief features. Even cheap connectors are made out of copper, though I'm sure there are some companies making them out of other materials.

    If soldering was safer or more reliable than crimping, that is what government safety regulations would mandate, but they don't.

    Solder fails during catastrophic events, creating more risk. It only takes ~360° to melt solder, any fire would do that, almost any short will reach that temp. You can reach that temp with less than 5W of power, a 10A fuse on a 12V system won't fail until it hits 120W.

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    Anybody who can read can see that you did in fact assert all the things you are claiming you didn't.

    Anybody who claims that others should take their word for something based on experience is doing so because it's the only thing they have when all the facts disprove their claims.

    I know and have met many, many "experienced" people who are utterly incompetent at their jobs. The longer a person holds the same job (not necessarily the same exact position, they usually get promotions and get moved around within the organization in order to not permanently inflict them on anybody) the less intelligence and imagination that person has. Intelligent people thoroughly learn the job and get bored with it and want to try something new. Dumb people are easy to keep interested because they never actually understand anything, so everything remains magical and new to them.

    Incompetent people don't know they are incompetent. It's called the Dunning-Kruger Effect.

    I had a Computer Science instructor in university who was in his late fifties or early sixties and had co-written the textbook for the course. One day I had trouble understanding his "pseudocode" and couldn't get a very short program of 15 lines or so to work, so I went to his office and asked him to go over the pseudocode with me. He wouldn't do that, and instead decided to debug my program for me, which is not what I wanted. I wanted to understand the the problem, not have him give me the answer. But he couldn't fix the program because he didn't even understand the procedure himself. So an hour and a half later I gave up, left his office and dropped the course. He was quite "experienced", but utterly incompetent. Meanwhile, another instructor was in his twenties and recently graduated but when I took a 2-page handwritten program to him in the classroom, he was able to point out the mistake in the time it took him to read to that point, which was a few seconds. Sorry, "experience" (or a certificate on the wall) is less than worthless.

    Everybody knows that government regulations are a giant mixed bag of everything from logical, reasonable mandates to utterly insane gibberish, and all too often regulations exist only because corporations make money from those regulations. So claiming something is correct just because it's a regulation is just as far off base as claiming someone is correct just because they've been around longer. If you can't stick to scientific fact then don't argue.

    No, crimp connectors do NOT have "stress-relief features". They may claim to, but unless they include something that actually has some give to it and bends easily with moderate pressure - and is in constant contact with the wire - it is just lip service. I have yet to see any such thing. (And no, the wire's own insulation does NOT qualify as "a stress relief feature".) As I said before, that's irrelevant anyway if you properly route and secure the wires. And I have never, ever seen crimp connectors in any store that contained any copper at all. They are usually aluminum or other soft alloys for splice connections and harder white metal for anything else. Years ago many things were manufactured with plated copper contacts that were silver on the surface but copper underneath, but I haven't even seen anything like that for many years, and never saw it in crimp products available to the average consumer. Again, what is available to an aircraft technician is probably entirely different than what is available to the average DIY-er in a consumer store.

    It's absolutely true that a soldering oven can simultaneously solder hundreds of miniature components on a circuit board exponentially faster and cheaper than an individual human can do the same job. Does that translate to larger scale and very different things like wiring harnesses? Not even remotely. And if soldered connections are melted in a vehicle, that's the least of your problems and you should be completely replacing the wiring anyway.

    1
    ShaneB112
    ShaneB112

    Reply 3 years ago

    Wo1fMane, you've misunderstood how resistors work. The wattage rating of a resistor is the maximum power the resistor is rated to dissipate, before possibly overheating or failing. If you choose a smaller wattage resistor, but still the same ohm resistance, you will be overloading the resistor, and it will likely overheat and fail. Maybe not immediately, it heavily depends on the overload severity, ambient temperature, duty cycle, etc... There is a simple calculator available online to determine what wattage resistor is required for a given voltage.

    Using this calculator, enter the voltage of an operating car ~ 14V, and the ohms of the chosen resistor - 6, and press calculate. You will see that this resistor will be dissipating 32.666 watts, and the 50 watt resistor used in this instructable is absolutely warranted.

    Your 6 watt resistors will STILL BE DISSIPATING 32.666 WATTS, and they are grossly under-rated for the application and will likely eventually fail. The only saving grace you have, is that during a turn-signal operation, they are only on about half the time, which will dramatically reduce the heat dissipation required by each. If we call the duty cycle 50%, then you are effectively dissipating 16.333 watts worth of heat through them, if averaged over time. This fact, coupled with the fact that turn signals tend to be operated in short bursts, is likely why your 6 watt resistors are still working... so far.

    Try leaving them on for a few minutes and see how hot the resistors get... Please have a fire extinguisher ready.

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    You've misunderstand how cars work. No turn signal bulb is anywhere near 50 watts. That's headlight territory. According to your calculations, the resistor will be dissipating more power than the original bulb. Also, my resistor is 6 Watts, not 6 Ohms. I never said how many Ohms my resistor was. Those other resistors need to be 50 Watts because they have too little resistance. You need rethink your approach.

    By the way, my "insufficient" resistors are still working fine more than a year later. But that's only because I haven't had the spare time to track down why the flashers I've tried to use don't work in spite of the pinout being correct according to the wiring diagram and the markings on the OEM flasher. Sooner or later, the resistors won't be necessary.

    0
    Wo1fMane
    Wo1fMane

    Reply 3 years ago

    There are too many problems with your calculations to list. But a glaring problem is that the resistors' values aren't actually given. Using that calculator, the 6 Watt resistor would have to be 32 Ohms, and the 50 Watt resistor would have to be 4 Ohms. But that ignores the rest of the circuit and that calculator only works for a single component. If you put a 4 Ohm resistor in series with the LEDs, and assuming the LED lamp draws a generous 1 Amp, you get a power dissipation of only 4 Watts and a voltage drop of 4 Volts across the resistor, which leaves 10 Volts for the LEDs. That's well within the operating specs of everything.

    0
    Wo1fMane
    Wo1fMane

    Reply 1 year ago

    See above. The point is that the whole point of those resistors is to draw enough power to "fool" the flasher into thinking you're using an incandescent bulb. So yeah, they're drawing a significantly large percentage of their rated power, and defeating the major purpose of LED lights, which is to save power and not throw off a bunch of waste heat.