LED Headlight Install - Need Help!

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BrowHeezy

New member
I bought a set of LED headlights and fog lights and the headlights won't turn on when installed. It should be real simple... Out with the old and in with the new, but it's not turning out that way. I hooked the lights up directly to a battery and they work just fine, it's only when they are connected to the Jeep that they don't work. I was told that I may need to swap out the relay but I can't find the headlight relay anywhere. I've been doing a lot of research but can't find any answers. Does anyone have an ideas on what I have to do to fix this and does anyone know where the headlight and fog light relays are in a 2010 JKU??? ImageUploadedByWAYALIFE1447344052.925612.jpg
 
WJCO

WJCO

Meme King
BrowHeezy said:
I bought a set of LED headlights and fog lights and the headlights won't turn on when installed. It should be real simple... Out with the old and in with the new, but it's not turning out that way. I hooked the lights up directly to a battery and they work just fine, it's only when they are connected to the Jeep that they don't work. I was told that I may need to swap out the relay but I can't find the headlight relay anywhere. I've been doing a lot of research but can't find any answers. Does anyone have an ideas on what I have to do to fix this and does anyone know where the headlight and fog light relays are in a 2010 JKU??? View attachment 173446
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Check fuses first. I remember Eddie saying that the left and right side lights run on separate fuses. If that's ok, then break out the DVOM and trace it. I do not know where the relay is. I assume in either the power distribution box under the hood or in the cab.
 
hinrichs

hinrichs

Caught the Bug
If your stock headlights work, I dont see a fuse being blown. What is that extra yellow wire for in that harness?
 
Goldeneagle1LC

Goldeneagle1LC

Member
They look like Night Sun. The yellow wire is for the strips on the top and bottom to be used as daytime running lights. They should just be plug and play. Are they connectors making good contact?
 
B

BrowHeezy

New member
Your right. The yellow wire is for DRL's. Everything is good and tight and the stock headlights work so it can't be the fuses. I'm at a loss.
 
WJCO

WJCO

Meme King
BrowHeezy said:
Your right. The yellow wire is for DRL's. Everything is good and tight and the stock headlights work so it can't be the fuses. I'm at a loss.
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Have you tried plugging your stock headlights back in since you removed them to verify that they still work? Just thinking of ideas. This doesn't make any sense. Only thing I can think of is there is a poor ground somewhere.
 
B

BertaNation

New member
When u ran the power direct from the battery. How did u connect it to the lamp? Just thinking maybe the wires are not making good contact in the plug
 
B

BertaNation

New member
I have basicly the same headlamp just from another vendor. Sometimes when I go down rough roads one of my headlamps will turn off. I am pretty sure it's due to the plug. It is a pretty loose connection when plugging in to the stock harness
 
B

BrowHeezy

New member
WJCO said:
Have you tried plugging your stock headlights back in since you removed them to verify that they still work? Just thinking of ideas. This doesn't make any sense. Only thing I can think of is there is a poor ground somewhere.
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Yeah, they're still working.

ImageUploadedByWAYALIFE1447346777.091050.jpg

I have a theory but I could be way off. On the light the positive (red I assume) is in the middle and its going to the black wire in the middle of the adapter harness. The ground (black wire) is off to the side going to the blue wire on the harness.

ImageUploadedByWAYALIFE1447347125.563399.jpg

Now on the Jeep, I'm not sure which wire is the positive but black is usually always the ground and its in the middle. Sooooo I have the positive from the light going to the negative in the Jeep right. I feel like that could be a problem but without cutting up all the harnesses and rewiring I'm not sure how to fix it.
 
B

BertaNation

New member
U should be able to find a wiring diagram on Google for the stock harness. I had thought about just cutting off my plugs and hard wiring mine.
 
WJCO

WJCO

Meme King
BrowHeezy said:
Yeah, they're still working.

View attachment 173447

I have a theory but I could be way off. On the light the positive (red I assume) is in the middle and its going to the black wire in the middle of the adapter harness. The ground (black wire) is off to the side going to the blue wire on the harness.

View attachment 173448

Now on the Jeep, I'm not sure which wire is the positive but black is usually always the ground and its in the middle. Sooooo I have the positive from the light going to the negative in the Jeep right. I feel like that could be a problem but without cutting up all the harnesses and rewiring I'm not sure how to fix it.
Click to expand...

That's possible but strange. Is the wiring like that on the working side too? Do you have a DVOM or test light where you could actually verify which wire is power and ground on the connector on the Jeep?
 
WJCO

WJCO

Meme King
Also, can you switch the new lights side to side and see if your non-working light works on the other side of the vehicle?
 
B

BrowHeezy

New member
Neither of the aftermarket lights work on either side and everything is wired the same way. I don't have a test light. I'm starting to think I really need to invest in one though. Lol
 
hinrichs

hinrichs

Caught the Bug
Here is a wiring break down I just found

LT side
Low beam White/Dark Blue
Return signal Black/light blue
High beam White/light green

RT side
Low White/tan
Return signal Black/light green
High White/gray
 
WJCO

WJCO

Meme King
BrowHeezy said:
Neither of the aftermarket lights work on either side and everything is wired the same way. I don't have a test light. I'm starting to think I really need to invest in one though. Lol
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Or even a cheap DVOM. I like the ones that have a audible buzzer for continuity too. Well worth having.
 
WJCO

WJCO

Meme King
Question: I assume you checked this. But you do have the dash switch in the 'on' position correct? Not on the DRL setting?
 
jedg

jedg

New member
Try this... I'm betting it works.

1. hook up LED headlamps

2. turn headlamp switch on WITHOUT starting the engine - if the LED headlamps come on then the below is your issue.

The headlamps on the JK work on the CANBUS with Pulse Width Modulation (PWM). If the CANBUS detects something wrong (like your low voltage LEDs) then it'll turn the circuit off. If I remember right, the PWM doesn't run when the ignition is off, so turning the headlamp switch to ON with no ignition ON should tell you if that's the issue.


If it is, the your choice is purchase a harness to trick the system or wire in your own resistor to trick the system.

EDIT- this sometimes manifests as the flicker that some folks talk about, sometimes it shows up as 'replacement headlamps don't work'
 
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WJCO

WJCO

Meme King
jedg said:
Try this... I'm betting it works.

1. hook up LED headlamps

2. turn headlamp switch on WITHOUT starting the engine - if the LED headlamps come on then the below is your issue.

The headlamps on the JK work on the CANBUS with Pulse Width Modulation (PWM). If the CANBUS detects something wrong (like your low voltage LEDs) then it'll turn the circuit off. If I remember right, the PWM doesn't run when the ignition is off, so turning the headlamp switch to ON with no ignition ON should tell you if that's the issue.


If it is, the your choice is purchase a harness to trick the system or wire in your own resistor to trick the system.

EDIT- this sometimes manifests as the flicker that some folks talk about, sometimes it shows up as 'replacement headlamps don't work'
Click to expand...

This makes sense. Anxious to hear the results.
 
B

BrowHeezy

New member
jedg said:
Try this... I'm betting it works.

1. hook up LED headlamps

2. turn headlamp switch on WITHOUT starting the engine - if the LED headlamps come on then the below is your issue.

The headlamps on the JK work on the CANBUS with Pulse Width Modulation (PWM). If the CANBUS detects something wrong (like your low voltage LEDs) then it'll turn the circuit off. If I remember right, the PWM doesn't run when the ignition is off, so turning the headlamp switch to ON with no ignition ON should tell you if that's the issue.


If it is, the your choice is purchase a harness to trick the system or wire in your own resistor to trick the system.

EDIT- this sometimes manifests as the flicker that some folks talk about, sometimes it shows up as 'replacement headlamps don't work'
Click to expand...

Ignition on or off the LED headlights still do not light up. I was thinking about buying PWM's like the ones that come with the truck-lites but wasn't sure if it would solve the problem. I've only heard of people having flickering problems not don't turn on at all problems without them.
 
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