Lx570 driver headlight electrical issue (1 Viewer)

[highfructose]

I think I solved this but figured I’d post here in case someone else has had this issue…or someone else has it at some point.

My 2011 lx570 seemed to lose its ability to turn on the low beam driver side headlight.

Even with a new bulb it still wouldn’t turn on.
Fuse that runs specifically driver side low beam is fine (tested and swapped to right).
Relay, I assume, is fine because I think it runs left and right at same time.

Weirdly though, the day time running lamp is on on the drivers side even though it’s disabled at infotainment center.

The internet recommended wiring inspection and jiggle tests.

While looking around I noticed that the headlight assembly module for the driver side bundles its wires and routes under the windshield fluid washer Fill spout….and that bundle is damp under the spot.

There is an o ring on an elbow for that washer fluid fill spout and mine appears to have lost its ability to hold when full…and I recently filled it.

So I suspect, as these cars age, that fill spot o ring and bundle of wires under it might intermittently contribute to driver side headlight electrical issues.

 

[highfructose]

Letting the area dry and ensuring no more washer fluid drained into it didn’t solve the issue. I’m going to try to fix this and log progress here in the event it helps someone else later (or someone here as suggestions).

Issue:

Primary: low beam seems to be getting too little voltage…resulting in relatively dim (aftermarket) led ignition (I replaced the led momentarily with new and it didn’t solve)

Secondarily, as well as oddly, DRL is active in same (driver side) headlight (even though it’s turned off in the infotainment center).

Attempts at
Diagnosing
Note: you might consider getting some very heavy gauge jumper cables if diagnosing an issue around the driver headlight so you can, while the battery is out, still make the car function (turn lights on)…my normal 4 gauge (not 0/4) worked to turn the power on, but the car wouldn’t run…I don’t think the electrical system will like the reduced voltage/amperage it receives via these thinner cables for long…so I plan to try some 0 gauge…may allow for 2-3 times more amps to flow.

• (Have to disconnect and remove battery to get in here, 12mm for battery brackets, 13mm for my battery terminals)…I also took two mini Phillips head screws out of the main headlight connector bracket to remove it from the headlight assembly.
• Main big bundle in back of headlight is not drl headlight power supply…drl still received power with it disconnected….exceedingly difficult to separate connector due to 15 years of dust making it in between the plastic…patient flexing and hook pick pulling for it disconnected…this appears, instead, to run the drl…drl connector, likely because it’s so much smaller, was far easier, with patient flexing and hook pick pulling to remove
• 

• Main big connector appears to be related to, at minimum, side marker and low beam (this was the hard one to disconnect)…I suspect this is so large because it also controls/powers the auto leveling/turning low beam housing.

Daytime running lamp stays on even when I pull all headlight (high and low) fuses…as well as the daytime running lamp relay…

Google says slot 59 is the daytime running lamp fuse though that’s an empty use in my block…and I’ve read in this forum that the DRL just peel off voltage from the high beam circuit…

which means, considering pulling the high beam fuses leave the driver DRL on, it may be the case that a wire some place has rubbed and is allowing voltage to be delivered to the DRL…

need to identify which wire is hot on drl connector…then use that color wire and trace it back to wherever it’s getting power (I think)

 

[highfructose]

Step 2

• Two main prongs on driver side low beam are receiving 11v
• Drl is receiving an oscillating 6-15v

Gonna trace back the drl wires

 

[highfructose]

Letting the area dry and ensuring no more washer fluid drained into it didn’t solve the issue. I’m going to try to fix this and log progress here in the event it helps someone else later (or someone here as suggestions).

Issue:

Primary: low beam seems to be getting too little voltage…resulting in relatively dim (aftermarket) led ignition (I replaced the led momentarily with new and it didn’t solve)

Secondarily, as well as oddly, DRL is active in same (driver side) headlight (even though it’s turned off in the infotainment center).

Attempts at
Diagnosing
Note: you might consider getting some very heavy gauge jumper cables if diagnosing an issue around the driver headlight so you can, while the battery is out, still make the car function (turn lights on)…my normal 4 gauge (not 0/4) worked to turn the power on, but the car wouldn’t run…I don’t think the electrical system will like the reduced voltage/amperage it receives via these thinner cables for long…so I plan to try some 0 gauge…may allow for 2-3 times more amps to flow.

• (Have to disconnect and remove battery to get in here, 12mm for battery brackets, 13mm for my battery terminals)…I also took two mini Phillips head screws out of the main headlight connector bracket to remove it from the headlight assembly.
• Main big bundle in back of headlight is not drl headlight power supply…drl still received power with it disconnected….exceedingly difficult to separate connector due to 15 years of dust making it in between the plastic…patient flexing and hook pick pulling for it disconnected…this appears, instead, to run the drl…drl connector, likely because it’s so much smaller, was far easier, with patient flexing and hook pick pulling to remove
• View attachment 3866607

• Main big connector appears to be related to, at minimum, side marker and low beam (this was the hard one to disconnect)…I suspect this is so large because it also controls/powers the auto leveling/turning low beam housing.

View attachment 3866608

Daytime running lamp stays on even when I pull all headlight (high and low) fuses…as well as the daytime running lamp relay…

Google says slot 59 is the daytime running lamp fuse though that’s an empty use in my block…and I’ve read in this forum that the DRL just peel off voltage from the high beam circuit…

which means, considering pulling the high beam fuses leave the driver DRL on, it may be the case that a wire some place has rubbed and is allowing voltage to be delivered to the DRL…

need to identify which wire is hot on drl connector…then use that color wire and trace it back to wherever it’s getting power (I think)

Letting the area dry and ensuring no more washer fluid drained into it didn’t solve the issue. I’m going to try to fix this and log progress here in the event it helps someone else later (or someone here as suggestions).

Issue:

Primary: low beam seems to be getting too little voltage…resulting in relatively dim (aftermarket) led ignition (I replaced the led momentarily with new and it didn’t solve)

Secondarily, as well as oddly, DRL is active in same (driver side) headlight (even though it’s turned off in the infotainment center).

Attempts at
Diagnosing
Note: you might consider getting some very heavy gauge jumper cables if diagnosing an issue around the driver headlight so you can, while the battery is out, still make the car function (turn lights on)…my normal 4 gauge (not 0/4) worked to turn the power on, but the car wouldn’t run…I don’t think the electrical system will like the reduced voltage/amperage it receives via these thinner cables for long…so I plan to try some 0 gauge…may allow for 2-3 times more amps to flow.

• (Have to disconnect and remove battery to get in here, 12mm for battery brackets, 13mm for my battery terminals)…I also took two mini Phillips head screws out of the main headlight connector bracket to remove it from the headlight assembly.
• Main big bundle in back of headlight is not drl headlight power supply…drl still received power with it disconnected….exceedingly difficult to separate connector due to 15 years of dust making it in between the plastic…patient flexing and hook pick pulling for it disconnected…this appears, instead, to run the drl…drl connector, likely because it’s so much smaller, was far easier, with patient flexing and hook pick pulling to remove
• View attachment 3866607

• Main big connector appears to be related to, at minimum, side marker and low beam (this was the hard one to disconnect)…I suspect this is so large because it also controls/powers the auto leveling/turning low beam housing.

View attachment 3866608

Daytime running lamp stays on even when I pull all headlight (high and low) fuses…as well as the daytime running lamp relay…

Google says slot 59 is the daytime running lamp fuse though that’s an empty use in my block…and I’ve read in this forum that the DRL just peel off voltage from the high beam circuit…

which means, considering pulling the high beam fuses leave the driver DRL on, it may be the case that a wire some place has rubbed and is allowing voltage to be delivered to the DRL…

need to identify which wire is hot on drl connector…then use that color wire and trace it back to wherever it’s getting power (I think)

I traced wires back a little ways and everything looked good.

So tested a few of the pins on the vehicle side connector/harness for the DRL’s and low beams…and the vehicle seemed to be sending comparable signals to Passenger and driver headlight.

So I removed the driver headlight and plugged it into the harnesses on the passenger side (probably should have used extended probes to do this though it ended up being the case the headlight is likely faulty, so it was going to come out anyway)

(all those harnesses on the headlights essentially require you to depress the lever…and then use a screw driver to carefully pry/separate the harness/connector)

The driver side headlight when plugged into the passenger side harnesses exhibited the same issues: constant DRL and low voltage (I assume) to only partially ignite the led in the low beam.

It seems to be the case that there may be some internal issue inside the headlight l (headlight removal was straight forward…all 10mm mounting bolts accessible with a floppy ratcheting 10mm wrench and 10mm shortwell on very long extension-though with my ironman bumper a lot of the plastic has been removed so this may be more involved with a standard vehicle).

I attempted to disassemble the headlight assembly. It appears to have been sealed/glued shut (which makes sense)…it doesn’t look like it’s serviceable (the plastic gives before the sealant if you try to pry).

81170-60d31 Is the part number for driver side.

$828 plus the drive to and from the dealer…or $521 shipped from Lexus parts now…seems to be the best deal for it right now.

 

[lx570weekendtoy]

Hi,
This is a very timely post. Having a similar issue with the driver side low beam. It was flickering for the longest time and then went kaput. In my case, the fuse was blown. Thought it might have been because of the bad bulb. Replaced the bulb and the fuse and it flickered and died. Checked the pins on the switch under the steering wheel and it all looked fine. Also right headlight working fine. Took it to a regular shop and they told me it’s probably the balancer/ballast/igniter and to take it to the dealer without actually looking at it as they said it could be another issue.
Lexus tech said that it was not throwing any codes, he swapped the balancer to the right and it was working fine. Said it’s an issue with the headlight itself. Wants to charge $3000 to replace headlight and balancer on drivers side only. Thinking about replacing myself but before that I don’t understand why it could be headlight. All other fused connections for headlight (high beam, DRL, motor) are separate fused connections. Low beam seems to be battery to switch to fuse to ballast to bulb. It has to be something in that chain and not the headlight. I don’t have the schematic but if you do, can you advise if the headlight replacement fixed your issue or if you also had to replace the ballast?

 

[highfructose]

Hi,
This is a very timely post. Having a similar issue with the driver side low beam. It was flickering for the longest time and then went kaput. In my case, the fuse was blown. Thought it might have been because of the bad bulb. Replaced the bulb and the fuse and it flickered and died. Checked the pins on the switch under the steering wheel and it all looked fine. Also right headlight working fine. Took it to a regular shop and they told me it’s probably the balancer/ballast/igniter and to take it to the dealer without actually looking at it as they said it could be another issue.
Lexus tech said that it was not throwing any codes, he swapped the balancer to the right and it was working fine. Said it’s an issue with the headlight itself. Wants to charge $3000 to replace headlight and balancer on drivers side only. Thinking about replacing myself but before that I don’t understand why it could be headlight. All other fused connections for headlight (high beam, DRL, motor) are separate fused connections. Low beam seems to be battery to switch to fuse to ballast to bulb. It has to be something in that chain and not the headlight. I don’t have the schematic but if you do, can you advise if the headlight replacement fixed your issue or if you also had to replace the ballast?

Many modern vehicles have headlight control unit of some sort, usually external from the headlight itself.

The first gen lx570 has one that’s integrated inside the headlight and this isn’t serviceable (you can’t really disassemble the headlight…it’s glued and screwed together).

If the headlight starts acting up the easiest way to confirm where the issue lies is to:

run disconnect the goofy light from the vehicle…and then run leads from the functioning side to the non functioning side and see if the problem swaps sides (or fully remove the goofy headlight and physically move it to the good side and plug the harnesses from the good side into it…though that’s a lot more labor if you’re just trying to diagnose)

In my case even when I plugged the driver (goofy) side headlight into the passenger side harnesses, the issue persisted…meaning it wasn’t vehicle side (fuses, bcm, relays, associated wiring), it was a headlight issue.

If I had to do it again, I would probably try to bypass the internal control unit…I’d splice a dedicated relayed circuit from the outside to isolate the low and high beams so they turned on when I wanted…almost as though they were auxiliary lights (I’ve got my auxiliary lights wired/relayed to turn on with my brights/high beams for instance).

The entire headlight was like $500 for an oem new one shipped. Used they’re like $250-$350, but I wouldn’t recommend used since the control unit inside in those likely also has a 10-15 year lifespan…so they might be getting ready to go too.

Imo a headlight and replacement from the dealer shouldn’t cost more than 1500 total…they’ll charge you like 750 for the headlight and probably 750 for labor. Do it yourself and it’ll cost 500 for the part…and 3-4 hours of your time. You just need a good quality 1/4” ratchet and socket set imo to do this

 

[lx570weekendtoy]

Thanks for the quick reply and explanation. The part you quoted was for a 2011. The part for 2013 seems to be 81185-60F80 and is
double the price at $1047. Still cheaper than the $2k part dealer is quoting though. And if I do it myself I will save on the labor.

https://www.lexusdirectparts.com/oem-parts/lexus-composite-headlamp-8118560f80?c=YT1sZXh1cyZvPWx4NTcwJnk9MjAxMyZ0PWJhc2UmZT01LTdsLXY4LWdhcw%3D%3D

 

[UT08LX570]

Many modern vehicles have headlight control unit of some sort, usually external from the headlight itself.

The first gen lx570 has one that’s integrated inside the headlight and this isn’t serviceable (you can’t really disassemble the headlight…it’s glued and screwed together).

If the headlight starts acting up the easiest way to confirm where the issue lies is to:

run disconnect the goofy light from the vehicle…and then run leads from the functioning side to the non functioning side and see if the problem swaps sides (or fully remove the goofy headlight and physically move it to the good side and plug the harnesses from the good side into it…though that’s a lot more labor if you’re just trying to diagnose)

In my case even when I plugged the driver (goofy) side headlight into the passenger side harnesses, the issue persisted…meaning it wasn’t vehicle side (fuses, bcm, relays, associated wiring), it was a headlight issue.

If I had to do it again, I would probably try to bypass the internal control unit…I’d splice a dedicated relayed circuit from the outside to isolate the low and high beams so they turned on when I wanted…almost as though they were auxiliary lights (I’ve got my auxiliary lights wired/relayed to turn on with my brights/high beams for instance).

The entire headlight was like $500 for an oem new one shipped. Used they’re like $250-$350, but I wouldn’t recommend used since the control unit inside in those likely also has a 10-15 year lifespan…so they might be getting ready to go too.

Imo a headlight and replacement from the dealer shouldn’t cost more than 1500 total…they’ll charge you like 750 for the headlight and probably 750 for labor. Do it yourself and it’ll cost 500 for the part…and 3-4 hours of your time. You just need a good quality 1/4” ratchet and socket set imo to do this

By first gen lx570 I assume you're referring to the 08-11, they do not have any modules or electronics inside the headlights, aside from the horizontal AFS motor. That only controls the horizontal adjustments of the low beam, has nothing to do with any other bulb or light emitting component. Ive had a few of these open for custom builds and they are very simple.

 

[highfructose]

By first gen lx570 I assume you're referring to the 08-11, they do not have any modules or electronics inside the headlights, aside from the horizontal AFS motor. That only controls the horizontal adjustments of the low beam, has nothing to do with any other bulb or light emitting component. Ive had a few of these open for custom builds and they are very simple.

You’re probably right. Was there a bank of connections, if not a module, inside it?

Because there’s something downstream of the connectors that attach the headlight to the car…

like there’s something INSIDE the headlight that can go electronically bad and send improper voltage to the high beams and low beams.

I call it a module. It might just be a bank or manifold that receives and then distributes electricity to the various components inside the headlight.

 

[UT08LX570]

You’re probably right. Was there a bank of connections, if not a module, inside it?

Because there’s something downstream of the connectors that attach the headlight to the car…

like there’s something INSIDE the headlight that can go electronically bad and send improper voltage to the high beams and low beams.

I call it a module. It might just be a bank or manifold that receives and then distributes electricity to the various components inside the headlight.

There is not. Wires go directly from the main connector, through a grommet and to the correct bulb. No modules or anything else inside.

 

[highfructose]

There is not. Wires go directly from the main connector, through a grommet and to the correct bulb. No modules or anything else inside.

View attachment 3938635

Dang. Maybe it was just the headlight side connector of mine that was bad. I really should have hard wired and avoided the headlight side connector altogether.

Odd…you wouldn’t think just a connector would go bad, but it appears maybe so…because multiple functions of the headlight were sperging out. Thanks for the info.

 

[lx570weekendtoy]

There is not. Wires go directly from the main connector, through a grommet and to the correct bulb. No modules or anything else inside.

View attachment 3938635

Do you know if that is the case for the 2013 LX570 headlights as well? Lexus tech seemed to indicate to me that there was an integrated control unit in the headlight but English was also not his first language and there might have been an opportunity for misunderstanding.

 

[UT08LX570]

Do you know if that is the case for the 2013 LX570 headlights as well? Lexus tech seemed to indicate to me that there was an integrated control unit in the headlight but English was also not his first language and there might have been an opportunity for misunderstanding.

I havent had the 13-15 set open for customization yet but the only thing thats different about them is the HID ballast on the bottom and the module/led driver for the DRLs. The DRL driver is completely separate from any kind of low beam power. Those would be the only differences.

 

[lx570weekendtoy]

I havent had the 13-15 set open for customization yet but the only thing thats different about them is the HID ballast on the bottom and the module/led driver for the DRLs. The DRL driver is completely separate from any kind of low beam power. Those would be the only differences.

Update. I called BS on the Lexus technician and service advisor and took it home and replaced the HID ballast and fuse. Paid $30 for parts to fix the issue and saved $2970. Thanks.

 

[UT08LX570]

Update. I called BS on the Lexus technician and service advisor and took it home and replaced the HID ballast and fuse. Paid $30 for parts to fix the issue and saved $2970. Thanks.

Love it! I often have a hard time believing dealerships when it comes to anything headlight related.