1G (1GA) New LED Headlights only on high or low but can't switch between.

[gusu]

Hello everyone,

I know the title is a bit confusing but I'll explain with a bit of backstory. I recently purchased new LED headlights and a wiring conversion cable knowing I'd likely have to swap pins thinking it should be "easy".

I bought these headlights

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and this adapter

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.

I've tried several configurations and got them working as shown below

• Low Beam - Switched to low beam (as intended)
• Low Beam - Switched to High beam
• High Beam - Switched to low beam
• High Beam - Switched to High Beam (as intended)

Now the problem is no matter how I move the pins on the harness I can only have high beams or I can only have low beams.

Following Steve's advice in this thread https://www.dsmtuners.com/threads/headlight-wiring-1ga-and-1gb-need-some-help-please.382670/

• Red/Blue - Power (common to both high and low)
• Red/White - Ground Low beam
• Red - Ground High beam

Using this method when using the adapter to pinout the same way the Amazon listing shows only gets me high beams when high beams are toggled and no low beam..

Thanks for any advice you guys can give.

 

[1990TSIAWDTALON]

I would take the light out and play with the different wires to make it switch from a comfortable place then, knowing what makes it switch, go out and alter what you need. I found on the 1gb, I had to reverse a wire to get my set to work but they are 2 different bulbs where you have one with a different amount of LEDs lit to be on hi or low. I know that is absolutely no help but it's how I got my 1gb to wire up and work great. Once you figure the wiring out, you'll love the LEDs.
Are the bulbs wired up like this???:

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[SouthIndy_Talon]

I believe your issue is the fact that the car switches the ground connection from the factory (“common power”). However, most bulbs these days switch the power side to toggle the high low beam (“common ground”).

There are conversion boxes out there that would make this common “power” to “ground” switch (seems popular in the older Toyota Supra circles). I have not actually tried it myself yet, so you mileage may vary.

Based on my findings a couple of years ago, you won’t be able to get high and low beams with just that conversion harness.

I also had an issue where the LEDs would only be at like 50% brightness if I have LEDs in both headlight locations. If it was one halogen and one LED, the LED would be full power. Not sure if that is an issue with my bulbs that I was trying to run or if there was another issue somewhere with how the headlight circuit works in my 90. I have ideas in my head to get it all working, but haven’t tried to execute it yet since I haven’t really gotten the car out this year due to a master cylinder issue.

But just something to look out for as you move forward.

 

[steve]

If those lights are common ground like the picture show you'll need to use some relays to run them. The factory wiring can be used to activate the relay and it can switch the high side to the lights.

Incandescent lights don't care if the wiring is common power or ground.

 

[1990TSIAWDTALON]

Exactly as Steve just mentioned. Use a 5 pole relay to switch between the 2.

 

[gusu]

Thanks guys, that makes a lot of sense to me.

 

[chrisman287]

I’ve used diodes before on other cars (9004/9007). 1N4007

Bridge the diode from low beam power to high with stripe facing the low beam.

God awful illustration (for diode orientation) but you would stick a diode inside each factory harness before plugging in the headlight connectors.

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