High beam intermittently on after headlight retrofit

[ko2]

Background:
I recently retrofitted a set of Morimoto MLED 2.0's in a set of OEM LX470 headlights. This means that both my low and high-beam harnesses plug into the control box and run off of the single projector. Throughout the retrofit I have tested everything and never noticed any issues, but I never had them on longer than 10-15 minutes. Previous to the retrofit, the headlights worked with no issues.

The problem:
Sometimes when I turn the truck on with the headlights set to "Auto", only the driver-side high-beam will stay on. If I turn the headlight stalk to OFF, that same high-beam stays on. If I turn it to "-", it stays on. But if I turn the stalk to "headlight on", both headlights turn on as they should. Like I said, this is intermittent. Sometimes it doesn't happen, sometimes it does.

What I've tried:
I have unplugged the DRL box in the engine bay. This didn't fix the problem.

Before I go back and double check the wiring harness, has anyone experienced something like this before? Thanks!

 

[LJE]

I can't help you with your issue, but curious what you think of the MLED 2.0s & how the install went!

 

[ko2]

I can't help you with your issue, but curious what you think of the MLED 2.0s & how the install went!

I’m a huge fan for many reasons. The light output is absolutely amazing. The cutoff is night and day better than the “Anzo” brand lights that the previous owner installed on the truck.

The parts themselves feel like they’re top quality. The projectors, wiring and control box feel like they were made to last a while rather than made to fit a certain price point.

They aren’t cheap but I’m very happy I went with them, current issues aside.

Install was relatively simple. I had to enlarge the chrome shrouds which took some precision to look good. Cooking them in the oven to get the lenses off was nerve wracking but went relatively well.

Happy to support if you do end up picking some up. There are some really great threads on here that helped me.

 

[LJE]

I’m a huge fan for many reasons. The light output is absolutely amazing. The cutoff is night and day better than the “Anzo” brand lights that the previous owner installed on the truck.

The parts themselves feel like they’re top quality. The projectors, wiring and control box feel like they were made to last a while rather than made to fit a certain price point.

They aren’t cheap but I’m very happy I went with them, current issues aside.

Install was relatively simple. I had to enlarge the chrome shrouds which took some precision to look good. Cooking them in the oven to get the lenses off was nerve wracking but went relatively well.

Happy to support if you do end up picking some up. There are some really great threads on here that helped me.

Gotcha! Thanks for that info. Does the integrated cooling fan end up outside of the housing so it can get relatively cool air?

 

[ko2]

Gotcha! Thanks for that info. Does the integrated cooling fan end up outside of the housing so it can get relatively cool air?

It’s inside the light. I haven’t seen any issues in the short amount of time I’ve ran them. I do know there are some vent holes in the lights that may help with airflow but I’m definitely no expert.


On another note, I found out the problem isn’t intermittent. The high beam problem starts when I take the ebrake off. If I idle with the ebrake on, it all functions correctly.

 

[LJE]

It’s inside the light. I haven’t seen any issues in the short amount of time I’ve ran them. I do know there are some vent holes in the lights that may help with airflow but I’m definitely no expert.


On another note, I found out the problem isn’t intermittent. The high beam problem starts when I take the ebrake off. If I idle with the ebrake on, it all functions correctly.

According to the FSM, the DRLs turn off when the E-brake is engaged.

So you're saying that when the headlights are set to AUTO, with the E-brake engaged, both high beams will come on (assuming you're in the dark/night) as they should, but then when you disengage the E-brake that only one high beam comes on via AUTO?

Looks like the DRL relays might cause some of this too - checkout the diagnostic chart attached too:

 

[2000UZJ]

Somebody with TechStream, have them turn the DRL's off. Since you are in CA, your truck might be wired to run them either way due to your DOT Laws.

I run my MLED 2.0's around the clock in my 100, no issues at all. I disabled my DRL's so I don't have this issue and can go dark.

 

[ko2]

According to the FSM, the DRLs turn off when the E-brake is engaged.

That’s incredibly helpful information thanks a ton for looking into it.

When I turn on the truck with the ebrake on,the lights work correctly. As soon as I take the ebrake off the one high beam turns on.

Somebody with TechStream, have them turn the DRL's off. Since you are in CA, your truck might be wired to run them either way due to your DOT Laws.

I run my MLED 2.0's around the clock in my 100, no issues at all. I disabled my DRL's so I don't have this issue and can go dark.

Much appreciated! I have an older Mac and I bought the tech stream obd cable. I just need to learn how to install it all.

I suppose disabling via tech stream is the better option vs unplugging the drl box, which didn’t do anything for me.


I messaged someone from Lightwerkz and they had mentioned that they have seen this issue before. They built a harness to power both high beams off of the passenger side high beam connector.

 

[2000UZJ]

That’s incredibly helpful information thanks a ton for looking into it.

When I turn on the truck with the ebrake on,the lights work correctly. As soon as I take the ebrake off the one high beam turns on.


Much appreciated! I have an older Mac and I bought the tech stream obd cable. I just need to learn how to install it all.

I suppose disabling via tech stream is the better option vs unplugging the drl box, which didn’t do anything for me.


I messaged someone from Lightwerkz and they had mentioned that they have seen this issue before. They built a harness to power both high beams off of the passenger side high beam connector.

That harness would be from @Luke111. I had a shop disable mine, took a few minutes and didn't change anything (was doing an oil change at the time)

 

[ko2]

Thanks to both LJE and 2000UZJ for helping me out. I finally got off my ass and got techstream installed and disabled the DRL's.
It seems to be working correctly now!