2013 LX570 flickering low beam $3k fix?

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Posted this as a reply to someone having a similar issue but thought id make a new thread for visibility. 2013 LX570 that I picked up a year ago. Drivers side headlight was flickering occasionally and got worse until it gave out recently. Replaced the bulb, did not work. 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 started but flickered and died. Fuse blew again. Checked the pins on the switch under the steering wheel and it all looked fine. No noticeable damage to wiring. 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. Does not make sense to me. Thinking about replacing myself if I have to as dealer wants to charge $3k, 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 path 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 someone does, can you advise if the headlight replacement makes sense or if I should just need to replace the ballast? PFA

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Here’s a link to wiring diagrams and a fuse location spreadsheet. Fo 2013 LC. Not sure of LX differences.

 
You should be able to source just the ballast (new or used). I had a similar issue with my Volvo whereby water found its way into the ballast and ruined it. I found the part number and bought a used one. Interestingly, the same Valeo ballast was used on Chrysler 300s.
 
Before I changed a part, I’d look real carefully at wiring. Symptoms are similar to an intermittent short in wiring that sometimes gets bad enough to blow a fuse. A mouse chewed wiring harness could do that.
 
It's not an issue with the headlight itself unless the main connector from body to headlight is damaged or corroded. They are very simple setups as long as wiring from body is getting power to the headlight. You can test the pinnouts on the connector to ensure the low beam positive is getting at least 12v.

The issue is likely the d4s bulb or denso ballast. Since you already replaced the bulbs, ballast is next. Having the headlight removed makes the process 100x easier since it is mounted on the bottom of the headlight and routed up to the bulb inside.

Definitely no need to replace the headlight. Dealers are dumb
 
It's not an issue with the headlight itself unless the main connector from body to headlight is damaged or corroded. They are very simple setups as long as wiring from body is getting power to the headlight. You can test the pinnouts on the connector to ensure the low beam positive is getting at least 12v.

The issue is likely the d4s bulb or denso ballast. Since you already replaced the bulbs, ballast is next. Having the headlight removed makes the process 100x easier since it is mounted on the bottom of the headlight and routed up to the bulb inside.

Definitely no need to replace the headlight. Dealers are dumb
I agree about the headlight, but it looks like the dealer swapped the ballast to the other side and it worked fine?
 
I agree about the headlight, but it looks like the dealer swapped the ballast to the other side and it worked fine?
I'd be surprised if they truly did, thats above most of their troubleshooting skills lol. If it's neither of those, the issue is pre-headlight wiring. Ballasts will flicker and prematurely die if run with less than 12v power is fed to them.
 
Dealer said there was a control unit integrated into the headlight that was the issue. Circuit diagrams linked above seem to bear that out. Given that it was not just the flickering and that the fuse blew twice seems to be a grounding issue that either points to that control unit, or the ballast or the wiring. Can’t find any damage to the wiring or evidence of mice. Also, live in suburbia and not the country. So process of elimination says ballast or control unit in headlight. Just my thoughts, not a pro by any means. Happy for another opinion.

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Dealer said there was a control unit integrated into the headlight that was the issue. Circuit diagrams linked above seem to bear that out. Given that it was not just the flickering and that the fuse blew twice seems to be a grounding issue that either points to that control unit, or the ballast or the wiring. Can’t find any damage to the wiring or evidence of mice. Also, live in suburbia and not the country. So process of elimination says ballast or control unit in headlight. Just my thoughts, not a pro by any means. Happy for another opinion.

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Update. Based on the information in this thread and another, decided to call BS on the service technician and service advisor and declined the replacement of the headlight and just took the car home. Paid $30 for a new ballast from Amazon and replaced the fuse. Issue fixed. Saved myself $2970. Had them refund me the diagnostic fee but I’m not going to get back the 6 hours I spent at the dealership. Also, just to confirm, contrary to what I said above, the light control ecu in the circuit diagram above is actually the ballast, also called computer assembly on some parts websites. There is no circuitry or controller in the headlight assembly part itself for 2013 LX570.
 
Can you post a link to what you bought at Amazon? Also where is the ballast located? I’ve got the same problem.

Chris
I bought this one which was $30
NewYall Xenon Ballast Headlight... Amazon.com: NewYall Xenon Ballast Headlight Control Unit Module D4S/D4R with Igniter Cable for Lexus for Toyota GS350 GS350 RX350 RX450h IS250 IS350 LS460 LX570 Avalon Sienna Venza 2011-2015 Forester Legacy : Automotive - https://www.amazon.com/dp/B08JTYDR4R?ref=ppx_pop_mob_ap_share

Alternatively if you want the Lexus part it’s 81107-75020

I found this video handy to help with replacement.


Also note that if your headlight was blinking for a while before dying and replacing bulb and ballast does not work, check the fuse and replace as needed
 
Update. Based on the information in this thread and another, decided to call BS on the service technician and service advisor and declined the replacement of the headlight and just took the car home. Paid $30 for a new ballast from Amazon and replaced the fuse. Issue fixed. Saved myself $2970. Had them refund me the diagnostic fee but I’m not going to get back the 6 hours I spent at the dealership. Also, just to confirm, contrary to what I said above, the light control ecu in the circuit diagram above is actually the ballast, also called computer assembly on some parts websites. There is no circuitry or controller in the headlight assembly part itself for 2013 LX570.
Awesome.

On another note, what size tires are you running?
 
Haha $3K for one side headlight? You could get a new OEM pair for that much with plenty of change left over.

And with your diagnosis (and fix) you seem more than capable of swapping out full units. Glad to see you fixed the issue for such little money.
 

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