Strange Headlight Issue
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Driver School Candidate
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From: CO
Strange Headlight Issue
2009 Lexus IS250
I was noticing a strange issue with my car's headlights shortly after I bought it (Sept. 2018): the high beam bulb (halogen) on the passenger side would turn off and on when I had the switch set to auto (I didn't test any other positions).
So I replaced the halogen bulbs with LEDs and am now seeing this:
Any ideas? Is it a switch somewhere? Bad ballast? Random Crazy Wackiness?
I was noticing a strange issue with my car's headlights shortly after I bought it (Sept. 2018): the high beam bulb (halogen) on the passenger side would turn off and on when I had the switch set to auto (I didn't test any other positions).
So I replaced the halogen bulbs with LEDs and am now seeing this:
- If I start the car and turn the switch to OFF, all the lights are off
- If I drive for an undetermined amount of time, the high beams will come on and flicker (actually it appears that once I release the parking brake, the problem arises)
- If I turn the switch OFF, they remain on and flicker
- If I turn the switch to AUTO, they remain on and flicker
- If I turn the switch to ON, they behave as expected (coming on only when the high beam switch is engaged and at full strength with no flicker).
Any ideas? Is it a switch somewhere? Bad ballast? Random Crazy Wackiness?
WAG but because each of the 4 lights are powered through relays it sounds like something is back feeding energy to the input of the high beam relay whereby it is enough energy to engage the relay and turn on your hi-beams.
Step 1: determine **what event** makes them flicker on if possible.
Step 2: ; find HB relay and remove it. With the high beams off, measure pins 1 and 2 and find out which is powered on when the high beams ARE switched on. Turn them off and monitor that pin to go high.
Step 3: in the event the HB still turn on with the relay removed, find the malicious wire tap and remove it. We'll sort out the issues after that.
As stated with the HB relay removed, those HB should never come on.
Step 1: determine **what event** makes them flicker on if possible.
Step 2: ; find HB relay and remove it. With the high beams off, measure pins 1 and 2 and find out which is powered on when the high beams ARE switched on. Turn them off and monitor that pin to go high.
Step 3: in the event the HB still turn on with the relay removed, find the malicious wire tap and remove it. We'll sort out the issues after that.
As stated with the HB relay removed, those HB should never come on.
You need a decoder kit for the LED. Try and contact ijdmtoy.com. I think the decoder I got was the R4 model they sell. Search on their website Decoders. As for the halogens follow what Fsport is saying.
Last edited by MikeFig82; Jan 11, 2019 at 09:45 AM.
^ second what MikeFig said.
you need a decoder kit for the LED since it's not meant to be powered at half voltage (which is what powers the halogen daytime running lights).
the decoder will, however, put your high beams, in full brightness no matter what.
the flickering is due to the LED bulbs receiving only a part of the voltage which it is not designed for, in DRL mode.
our highbeams aren't meant to be converted to LED, unless you disable the DRL.
you need a decoder kit for the LED since it's not meant to be powered at half voltage (which is what powers the halogen daytime running lights).
the decoder will, however, put your high beams, in full brightness no matter what.
the flickering is due to the LED bulbs receiving only a part of the voltage which it is not designed for, in DRL mode.
our highbeams aren't meant to be converted to LED, unless you disable the DRL.
^ second what MikeFig said.
you need a decoder kit for the LED since it's not meant to be powered at half voltage (which is what powers the halogen daytime running lights).
the decoder will, however, put your high beams, in full brightness no matter what.
the flickering is due to the LED bulbs receiving only a part of the voltage which it is not designed for, in DRL mode.
our highbeams aren't meant to be converted to LED, unless you disable the DRL.
you need a decoder kit for the LED since it's not meant to be powered at half voltage (which is what powers the halogen daytime running lights).
the decoder will, however, put your high beams, in full brightness no matter what.
the flickering is due to the LED bulbs receiving only a part of the voltage which it is not designed for, in DRL mode.
our highbeams aren't meant to be converted to LED, unless you disable the DRL.
Does that change your opinion?
I think the OEM HB harness has been molested in some way. A wire tap added for something I'd guess.
That said with the release of the parking brake, it does seem related to DRL...
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mikevanle
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