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I did some work under the dash on Friday, removed all the covers, steering cowl and the heating plastic duct under the steering wheel to get to the steering tilt/telescopic mechanism to grease the rollers. There is another post about this.
I put everything back together and went out in the car, set off down the road and the parking brake light was on - stopped the car and checked that the parking brakes was actually off and it was. Continued to where I needed to go - back home and removed all the covers to check if I’d disturbed anything - couldn’t see anything, wiggled wires, parking brake switch and connectors but couldn’t see anything.
I back off the drive onto the road and I can’t remember if the parking brake light was on or off when I reversed off the drive, only noticed it when I started diving down the road.
Went back and forth checking things etc a few times but couldn’t find anything, dodging the rain of course.
So today I remembered a post about a failed stop light causing the parking brake light to stay on, I got the Mrs to press the brake pedal while I checked at the back…….no brake lights left or right at all but the centre high level brake light works.
Maybe a fuse so off with the under dash cover and checked the fuses which are ok, checked the connectors to the fuse/connector block and they look ok.
Weather is atrocious so can’t start checking voltages to things or removing the rear lights or checking the brake failure module in the boot in this weather so I’m stuck without brake lights.
Has anyone any ideas about this by any chance?
I’ve disconnected the Battery and will leave it off for a while in the vain hope that it clears the issue.

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5 minutes ago, Malc1 said:

probably just BOTH stop lamp bulbs blown !

Malc

It is possible I suppose, I’ll check both of them if it ever stops raining………

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Both rear bulbs are ok. I must have done/disturbed something under the dash, probably round the junction/fuse block area I suspect.
When it stops raining and I have a good look at the wiring diagram tomorrow, I’ll take the under dash panels off again and have another look.
On Friday I was dodging rain showers so couldn’t spend a lot of time on it.

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3 hours ago, ambermarine said:

Check the brake light switch and connections under the brake pedal, it is adjustable.

Will do but I think it's ok because the high level brake light works ok.
I checked what is working and what is not working regarding rear tail lights and stop lights, while dodging the rain showers yesterday.
rear tail lights:       outer tail lights on the rear quarter work but not the inner tail lights on the boot lid
Stop lights:            high level works ok but non of the outer and inner

I've printed off the relevant circuit diagrams, plus anything else I think may be useful, had a good look and made notes of what to check when I get home.
I suspect a ground wire missing somewhere on the body, maybe under the dash or the Light Failure Sensor or the Light Failure Sensor itself is duff.
First port of call is to get under the dash again and have a good look round where I was working properly, I may have disturbed something.
Next in the boot, remove all the lining and start checking voltages and ground wires. Starting with the Light Failure Sensor module. I've read that the wires through the boot hinge/s can cause issues so will check that.

Circuit diagram for the Stop Lights. the section in Yellow I know works because it's the High Mounted Stop Light and it works.
On the Light Failure Sensor pins 1 and 8 should have 12 volts on at least one of them because the High Mounted Stop Light works
pin 3 and 4 feeds 12 volt to the stop lights - the 12 volts are staggered across the LH and RH stop lights - pin 13 is ground
At the other end of the Stop Lights there are 2 x ground points -  BN and BL
These are things I need to check.

image.thumb.png.c6ba2b9ddf7eae5a8ef50416c8ce5edd.png

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Too much of a coincidence that they stopped working after you were working on it.... However, it's happened to me many a time where I think it's the basics/obvious but then turns out to be something entirely different.

I think your logical approach should have the mystery solved quickly... fingers crossed of course! 🙂

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12 minutes ago, Supafly said:

Too much of a coincidence that they stopped working after you were working on it....

Yep, that was my initial thought but I only removed the lower covers - steering column cowling - the air/vent ducting and disconnected the aircon air sensor thing and rubber hose.
I've had all that off before except for the air/vent ducting and there isn't any wiring in the way that I had to move, unplug or disturb really.
I'll see what I find after work today, it could have been just coincidence but my gut/instinct tells me it's not..................

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Checked all round under the dash and I can’t see where I could have done anything untoward.
Boot linings out to get at all the wiring.
Checked thoroughly what does and doesn’t work.

Indicators - all ok
Fog lights - all ok - boot lid cluster? Can’t remember but they work.
Reverse lights on the boot lid clusters - all ok
Outer tail lights - ok

Inner boot lid tail lights - not ok
Inner boot lid stop lights - not ok - if there are any and maybe the stop lights are just on the outer cluster - I can’t remember.
Outer cluster stop lights - not ok

So on with checking voltages etc.
4 pin connector to each outer light cluster and disconnected to the light cluster - I have 12 volts on one pin on both outer light clusters when the brake pedal is depressed and 12 volts on another pin with the side lights switched on. The other pin will be the indicator, I didn’t check but will do tomorrow.
Same with the clusters connected and there is ground/earth. There is resistance to earth of 220 ohms iirc with the Light Failure Module connected on the 12volt pins but this goes iirc with the module disconnected. I did a lot of testing and should have wrote it all down but I’ll do that tomorrow.
I was mainly looking at the 12 volt supply to the light clusters and bulbs and there is 12 volts but the bulbs don’t illuminate. And yes I have checked the bulbs for continuity.
I’m a bit puzzled now cos I expected no 12 volts supply to the stop lights but there is.
The plan now is:
Tomorrow redo all the testing I did today and document it all exactly.
Plug in the laptop with Techstream and run a diags test and see what it says, I don’t expect much. Laptop was at work over the weekend so couldn’t do it. I have it back today but wanted to do some basic testing first.
Wednesday a used Light Failure Module should arrive, will fit it and see if that cures it.
If not then it will be time for an auto electrician or take it to Lexus for some diags.
If anyone has any advice or thoughts or suggestions based on what I’ve done and checked then please let me know, it would be appreciated.

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it's possibly just ancient wiring that's sadly piecemeal, in situ, fracturing slightly ......... and buggering about with it randomly just might be aggravating the fragility ..... suggest you try to find a competent AutoElectrician that understands what he's doing ....  believe me, many just don't and won't want to touch an aged car.

Lexus Main Dealer might have the same level of incompetence but considerably more expensive too

Good Luck

Malc

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Just realised I have the USA electrical diagram so the pin outs for the Light Failure Module are different and therefore the wiring is different, must be cos they don't match the car.
Has anyone got the UK Electrical Diagram by any chance and can send me the stop light circuit diagram please?

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42 minutes ago, Malc1 said:

it's possibly just ancient wiring that's sadly piecemeal, in situ, fracturing slightly ......... and buggering about with it randomly just might be aggravating the fragility ..... suggest you try to find a competent AutoElectrician that understands what he's doing ....  believe me, many just don't and won't want to touch an aged car.

Lexus Main Dealer might have the same level of incompetence but considerably more expensive too

Good Luck

Malc

Possible Malc and highly likely, I'll check again today round the areas I was working on.
I've already found a local Auto Electrician in case I need them, going to do more looking and diags i.e. checking the rear light clusters when disconnected with 12volts (using a power probe which will arrive tomorrow) to make absolutely sure all the bulbs light up.
Power probes allow you apply 12volts to stuff easily and safely, something I was meaning to buy but never got round to it.

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I think the inner boot lid lights don't work on our UK cars.  I'll see if I can get a picture for you from my car this afternoon to confirm.

Power probe was going to be my suggestion too, I'm the same, I have them on watch lists but haven't bought on yet.  I've been able to get by with a multi meter for now.  I think I should get one ordered too just in case.

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I might have missed it, but have you checked for continuity across the bulb itself, or alternatively take it out and use two lengths of wire across the Battery terminals to verify they both work?

 

Edit

Just re-read the thread and saw that you've confirmed that the bulbs are ok.

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1 hour ago, Supafly said:

I think the inner boot lid lights don't work on our UK cars.  I'll see if I can get a picture for you from my car this afternoon to confirm.

That would be great thanks
So that would mean the stop lights are only on the outer cluster and not on the boot lid lights.
That would make sense because iirc on the boot lid there are 2 x single filament bulbs either side, 1 x for tail light and 1 x for the reversing light

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5 hours ago, Supafly said:

I might have missed it, but have you checked for continuity across the bulb itself, or alternatively take it out and use two lengths of wire across the battery terminals to verify they both work?

 

Edit

Just re-read the thread and saw that you've confirmed that the bulbs are ok.

Mmmmh, I'm really doubting myself now........................I did check last week (I think) but it wasn't ideal dodging the showers so I will check again. I hope I've been a proper numpty and in the end it IS just the bulbs!!
I have a spare set of rear outer clusters, these were on the car when I bought it and all working. I swopped them because the lenses were cracked. Rather than taking the bulbs out of the existing clusters and checking them, I'll plug in the spare set and see what happens🤞
After thinking about it more, I think I only have 1 x issue which is 2 x stop lights out, one bulb either side in the outer clusters, when I thought I had 4 x stop lights out and 2 x tail lights
I thought the side lights and brake lights were on the boot lid as well and I figured all four bulbs cannot have gone at once plus 2 x tail lights but that is not the case I think, as said in the previous post on the boot lid there are 2 x single filament bulbs either side. I will check tonight but they must be for the fog lights, forgot about them, and reversing lights which both work.

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1 hour ago, Razor61 said:

which is 2 x stop lights out, one bulb either side in the outer clusters,

oh dear  .  I really hope it's as simple as I first suggested too  ..........  😇

Malc

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20230725_163554.thumb.jpg.6ca9c0d0a64094462a66e78504c0931d.jpg20230725_163620.thumb.jpg.83ec54142d652830d434bedede20bc96.jpg

It's still bright so the pictures aren't as clear as I would like.  The top pic is with the brake lights on and the bottom is sidelights on.

 

For clarity, the brakes are both lower outer and middle high.

Sidelights are upper outers.

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I had one fail a while ago.  I was surprised to find how dirty the lenses were for the number plate lights. I took them apart and cleaned them, it made a big difference to how bright the illumination was.

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Well……………..fitted the spare light clusters and all ok so it was the bulbs after all.
However, I checked the bulbs in the clusters in the car. One was indeed blown, I’m pretty sure it wasn’t blown when I checked last week but can’t be 100%. The other was a stop/tail bulb, didn’t fit properly in the light bulb fitting and didn’t work to begin with but was ok after a bit of tweaking.
I swopped both the bulbs from the spare light cluster and all is good now but the bulb socket on one side isn’t 100% so will order a complete set of bulbs and fit them to be sure.
After all that, it was just coincidence that the issue appeared just after I worked on the steering mechanism to grease it. I really couldn’t see how I had done anything or disturbed anything and it turned out I was right, no consolation but that’s life.
I could guess at what happened but I don’t care, it’s sorted now and I can relax.

Coincidence and thinking I had a bigger issue than I actually had caused all this.
At least I know how the lighting circuits work now and prompted me to buy a Power Probe which will be handy in future.
By the way, if the boot light bulb has blown or is disconnected the parking brake light will come on. That means the parking brake light ‘on’ can mean at least - parking brake still on - rear bulb gone - brake fluid low - boot light bulb gone or disconnected.

Thanks to everyone for their input, it’s appreciated and all this may help someone else.

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2 hours ago, Supafly said:

20230725_163554.thumb.jpg.6ca9c0d0a64094462a66e78504c0931d.jpg20230725_163620.thumb.jpg.83ec54142d652830d434bedede20bc96.jpg

It's still bright so the pictures aren't as clear as I would like.  The top pic is with the brake lights on and the bottom is sidelights on.

 

For clarity, the brakes are both lower outer and middle high.

Sidelights are upper outers.

Nice one, thank you for taking the time to do it👍

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