Headlight Dipping Problem

[Martin_W]

I have an IS300h purchased new August 2015, (approx 8000miles). It has recently come to my attention that the offside headlight does not always dip after being on high beam. The fault is intermittent. I did snag this on the 1 year service but was told by the dealership that there was no fault found. Recently the fault has become more frequent, and I have to dip the lights twice to get the off side to go down. This tends to annoy oncoming traffic. After investigations, and replacing some headlamp parts, and swapping parts L-R, the dealership is now sourcing a new O/S headlight unit to cure the problem.  Has anyone else experienced this problem or anything like it. 

[tayaste]

On the Lexus , The dipped / main beam is controlled by a signal from the headlamp ECU which requests a solenoid to activate a shutter / shade. 

The bixenon headlights on Land Rovers and range rovers sometimes have a similar issue where as the shutter sticks and needs freeing up.

With your car it sounds like it could be a sticky shutter or faulty solenoid.

[steve2006]

Technology gone mad....a Headlight ECU!

What happened to a switch and relay, another basic function made more complicated and it would appear more unreliable.

[tayaste]

Agree. Headlights are getting a lot more complicated they need to receive different inputs from different sensors nowadays like the rear height control sensor and acceleration sensor etc so it can adjust height / levelling. For adaptive headlights they need to read signals from the yaw sensor, steering angle sensor and speed sensors so they know how and when to turn. 

But, like you say. It can be a lot more difficult ( and more expensive )  to find the cause of the problems now when compared to the simple switch, relay and lamp.

[capese21]

7 hours ago, steve2006 said:

Technology gone mad....a Headlight ECU!

In the days of a Lucas sealed beam which were like candles, cars with a carburettor and a manual choke and points to replace & gap with a feeler gauge...I don't miss those days

[wh05apk]

I have noticed the same issue this evening getting flashed several times, my nearside is not fully dipping.

Unfortunately the warranty ran out a few weeks ago.... should have stuck with Hyundai or bought a Toyota would have got a decent warranty then.

[Simpsoid]

Me too!  I reported it to Lexus a year ago after I'd had my IS300H Exec for a couple of weeks, figuring perhaps they were just set too high but was assured they were MOT-legal.  Come into winter again now, of course, and have also had people flashing me angrily but have also come to realise the offside lamp does sometimes clearly light up higher and brighter on the road and the back of the car in front when it should be dipped.

I haven't tried the dip-twice trick but will do so.  Seems like I should book a new visit to Lexus Bristol, armed with this info, thanks!

 

[PhilWebster]

I have had the same issue but again very intermittent followed a mate to work yesterday got flashed by several  oncoming cars and when I got out the car he was moaning that I was blinding him with the offside headlight.I had reported this to Lexus when the car was in for the ventilation system but assumed that they had looked at this as it went away.parked car in front of a wall when i got home flashed the full beam on and off and a couple of times the beam seemed to stay high a couple of times.booked in for Lexus brum to look at it Monday. I'll update after then.  

[onisto]

 

I have the same problem, the seller told me that is due the shutter that does not close properly but remains oblique and partially opened.... I'd try to disassemble the headlight

[capese21]

Not worth disassembling it as the warranty is still valid even if possible. I would demand a new unit is fitted immediately. It is a safety issue.  

[onisto]

21 hours ago, capese21 said:

Not worth disassembling it as the warranty is still valid even if possible. I would demand a new unit is fitted immediately. It is a safety issue.  

My warranty has expired six months ago

[capese21]

1 hour ago, onisto said:

My warranty has expired six months ago

I have seen one or two breakers on eBay uk. I dread to think what a new unit would cost.

[wh05apk]

My warranty ran out 3 months ago,  I wonder if this was a faulty batch or is 3 years just the"normal"lifespan? 

[PhilWebster]

On 1/10/2017 at 4:40 AM, PhilWebster said:

I have had the same issue but again very intermittent followed a mate to work yesterday got flashed by several  oncoming cars and when I got out the car he was moaning that I was blinding him with the offside headlight.I had reported this to Lexus when the car was in for the ventilation system but assumed that they had looked at this as it went away.parked car in front of a wall when i got home flashed the full beam on and off and a couple of times the beam seemed to stay high a couple of times.booked in for Lexus brum to look at it Monday. I'll update after then.  

Car Been into Lexus for headlight issue .headlight was set too high so adjusted no sign of any other issue so we'll see how it is in the next few weeks 

[Dan_S]

 Hi Guys , I recently bought a late 2015 plate Lexus IS300H . I am pretty certain I have the issue with going from full beam headight to dip beams as I often get flashed by other roadusers . I also use the trick of pulling the dip lever twice which seems to get the lights onto dip beam. Its a very frustrating issue - has anyone any advice on how to get this fixed ? 

Thanks . Dan. 

[BigChange]

Similar problems with my 2015 IS300H.  I have manual full/dip controls and when moving from full to dip using the dip lever the change does not always happen The only way I know this is when I start getting flashed. I then pull the lever more forcefully and the beam dips.  It's a "sticky" lever and impossible to demonstrate at the garage.  Very difficult to have them replace the switchgear under warranty.  Really frustrating.

[Simpsoid]

I didn't update this thread since my original post, sorry, but I'm happy to report I did get it sorted on my car.

I stuck some sheets of paper to the inside back wall of my garage, cycled my lights through the 'proper' dipped and full-beam settings and drew on the sheets where the light *should* end for each.  I then recorded some video with my phone as I flicked several times from dipped to full beam and back manually and showed within about a minute that coming down from full to dipped didn't always work - it clearly stopped about half way between.

I presented this to my Lexus dealer and they replaced the light unit under warranty.  I did tell them I considered it a safety concern because it absolutely is, but I think they would have replaced it in any case as the evidence was clear.

I haven't noticed any issues with it over the last two years.

 

[BigChange]

Simpsoid, is your full/dip mechanism automatic or manual ?  Mine is manual and it is the quick 'flick' from full when driving which doesn't always fully dip the lights.

[Simpsoid]

Manual. The problem arose in two ways. Either:

• When the car started and turned the lights on (dipped) automatically, or
• I flick the stalk to full beam and then back to dipped

In both scenarios, especially in colder weather, it seems, it would leave my offside headlight about half way between proper dipped and full beam, maybe 1 out of 4 or 5 times.

Hope that helps.

[matt8]

Similar problem on my offside now. Seems worse in cold weather.

Is it that the reflector is stuck? Does it need rejigging a little?

Any tips welcomed. Seems a frequent issue judging from the number of people posting about it here.

[Lex_1988]

Ah looks like Ive got the same issue on the drivers side. It's a long shot but I was wondering whether the relax warranty would come to the rescue? It mentions headlight motor lifters but nothing on the shutter 

[matt8]

Someone kindly shared this video in another thread.

Does anyone think it's possible to access the shutter, jig it around and free it up a bit, without unsealing the headlight unit as a whole? Maybe a bit easier with the headlight removed.

In which case, anyone got a steer on how to remove the entire headlight? Bumper removal job I know.

 

[matt8]

I've found that toggling high beam on and off doesn't loosen it up really. It seems to be stuck / getting worse.

I've also found that a quick tap on the headlight (when I'm standing outside of the car) causes the stuck shutter to loosen and it falls back to place.

I had a quick look, but does anybody know if this might fall under a TSB. Are the lights flawed or do they have a design issue? I looked at lexus-tech.eu myself but couldn't see one.

I'd rather not take off the bumper and install a new light myself if I can help it, despite the great guide from @agent_dess recently! If it's a TSB then Lexus can do it despite no current warranty.

[agent_dess]

3 hours ago, matt8 said:

I've found that toggling high beam on and off doesn't loosen it up really. It seems to be stuck / getting worse.

I've also found that a quick tap on the headlight (when I'm standing outside of the car) causes the stuck shutter to loosen and it falls back to place.

I had a quick look, but does anybody know if this might fall under a TSB. Are the lights flawed or do they have a design issue? I looked at lexus-tech.eu myself but couldn't see one.

I'd rather not take off the bumper and install a new light myself if I can help it, despite the great guide from @agent_dess recently! If it's a TSB then Lexus can do it despite no current warranty.

I found a TSB for headlight condensation (US Market).. but Lexus UK fobbed me off saying its not in warranty and "it didn't leave the factory like that" so either its had an impact....  despite all that i found no valid reason for the condensation issue.  You can try speaking to Lexus but don't hold your breath.

Bumper and headlight removal is easy.

[umuk]

On 3/2/2022 at 12:23 PM, Lex_1988 said:

Ah looks like Ive got the same issue on the drivers side. It's a long shot but I was wondering whether the relax warranty would come to the rescue? It mentions headlight motor lifters but nothing on the shutter 

Hi. Did you get anywhere with this? I've got the same issue and have the relax warranty from servicing with Lexus. Thanks