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I replaced my standard halogens with LED lamp assemblies. I used Trux 5x7 TLED-H4. Hey were pricey but nice looking setup. There were two little aluminum locating keys that I had to file down because they interfered with the light bucket. I am very pleased with the lights. They give out an awesome bright pattern. I am having an issue. If the key is on (car started or not doesn’t matter) everything works well. If the key is not turned to the on position the high beam indicator does not work and there is a small amount of bleed voltage that will keep the high beam slightly lit when you are on low beam. Again this will not happen with the key on. Has anybody experienced this issue ? Thanks
The blue indicator does not function unless the key is in RUN.
Explanation: The blue indicator is controlled by the CCM. The CCM receives an input from the High Beam circuit, and turns on the blue indicator. The CCM controls the intensity of the blue indicator depending on ambient light, dash light dimmer position, and park/tail lights on or off. The CCM is only active when the key is in RUN.
Thank you for the reply. It makes sense. There is a slight voltage leak back to the high beam when the low beam is on. Do you know the cause? Do I need to install a resistor to add a little more load? Thanks again
I read this several times and still am not sure of the meaning of "bleed voltage that will keep the high beam slightly lit when you are on low beam". Do you mean the High Beam indicator is slightly lit or the actual high beam element in the LED headlight unit?
I have a set in my 92 that a friend gave me, unknown brand. While I don't drive it night they look really cool (yes I'm a boomer) when the hood is up. But the bulbs themselves and indicator all function as before the LED install.
There is a slight voltage leak back to the high beam when the low beam is on. Do you know the cause?
With the low beams ON, try turning the fog lights off and on with their switch. If the fog light on/off influences the "slight voltage leak", then it is the way the fog light relay is wired that is causing the "leak". Yes, a load resistor or even a 168 light bulb between the lt green and black wires in just one headlight housing will alleviate the "bleed".
Some peeps will advocate and suggest "cut the lt green wire at the relay and ground it". This can be challenging just to access the wire at the relay. I'd do the 168 bulb. There's a long thread about solving the issues LED headlights cause by using the 168. << I put a link to the thread in the next paragraph.
EDIT/ADD: Here's a pic of the 168 bulb added to the LED headlight harness. doing it this way doesn't cut or molest any original car wiring. The thread that discusses this is here, but the thread contains a lot of fluff and noise making it difficult to find information you can use. The opening post has some useful information including a circuit diagram that shows the fog light circuit. Cheers.
Regarding the bleeding high beam light, to summarize :
Key not turned on (no ignition), low beam enabled --> high beam bleeding.
Key turned on (ignition or run), low beam enabled --> no high beam bleeding.
From the headlight perspective there is no difference between these two scenarios. It is still receiving 12V on the low beam side and nothing on the high beam side.
The only things that changes when the ignition is set, is probably that more CCM interface chips are up and running. It is possible that the high beam circuitry within your LED H4 assembly get accidently slightly supplied or grounded via the "HIGH BEAM IN" interface of the CCM. the CCM might not be fully configured when the ignition is not set (this interface could be set as an output instead of an input and slightly drive the high beam, or the opposite and leak current)...who knows.
It cannot leak via the fog light relay as there's a diode in the light switch.
If you could do the following measurements :
Disconnect the headlight from the car harness and make the connections with wires between harness and headlight (low beam to low beam, ground to ground). Leave the high beam connection open. Enable the low beam. Do you still see bleeding ?
YES, bleeding observed : bleeding is caused by the internal circuitry, backpowering the high beam circuitry. Design issue of the headlight obviously. No idea why it's no longer a problem when ignition is set. I highly doubt that's the problem.
NO, no bleeding observed : bleeding is caused by the connection to the CCM (either getting power from the CCM or leaking current through the CCM).
Getting power from the CCM : a small diode with low forward voltage, cathode toward CCM will prevent this, while maintaining the blue indicator feature. To know if you get power from the CCM, simply measure the voltage in the car harness (high beam contact). If you measure something, it means that the CCM is powering the high beam.
Leaking current through the CCM : a large diode with low forward voltage (capable of handling high beam current), cathode toward headlight will prevent this. To know if you get current leak through the CCM, simply measure the voltage on the headlight (high beam contact). If you measure something, it means that it could induce current into the CCM.
One thing i know for sure is that the front-end interface for the CCM "High Beam In" is the following one. So it has capability of sinking current (especially in R74).
You can also insert a multimeter (current mode) in between the headlight and car harness (high beam link) to in which direction the current is flowing, if any.
Schematic for info (i'm hidding the headlight structure as the electrical properties of a LED headlight are completely different from standard bulbs in your scenarios).
I'm curious about the results if you're motivated enough to conduct the experiement...This is just an assumption.
Thank you so much for all of the info. Looks like I have some homework to do. I have to find the time to turn the heat back on in the garage and dig into it. I am interested in the results and will post it. I forgot to mention I do have LEDs in my fog lamps and can not say for sure but there was an anomaly with them but I forgot the issues. I will better document. Thanks again for all of your time spent with the descriptive explanations
LED Headlight replacement issue
