Central Locking/elec Windows/interior Light Not Working

[Wez_LS400]

Hi all,

I'm on the hunt for any pointers from you knowledgeable lexus folk.

I've had a MK4 LS400 for many years now, without ANY problems, but, lately my central locking has stopped working, both using key in door and using the remote on the key (3 button key - boot/lock/unlock). LED on key lights when I press buttons. I can use the key in the lock but only unlocks the door im using it in.

Also, at the same time, my electric windows have completely stopped working, as well as my interior light not coming on with the door open (i have checked the switch on the light is on 'door' setting)

Also if i leave my headlights on and open my door, i dont get the reminder noise any more.

Odd thing is, the windows do sometimes intermittantly spring back into life.

about 4-5 months ago when i opened the car (via remote central locking) all of the windows went down at same time automatically... this was around the time the problems started.

So....

Any ideas folks? I dont want to write the car off, looking tired now at 250k miles but still goes like the day i bought her, just without central locking and opening windows :(

Many thanks for looking.

[Wez_LS400]

sorry, forgot to add, the button on the drivers door to operate the seatbelt height adjust doesnt work either... passenger one works fine.

I have checked all fuses/diodes/relays in fuse boxes (engine bay and under steering wheel)

thanks

[SteveLS400]

Morning Wez and welcome.

Firstly there is a massive resource here - the search facility. Please plough your way through it using different terms, like windows, doors etc etc.

Secondly, and for what its worth is my thinking. I'm tempted to suggest some poor connections within the drivers door could be responsible for most of the problems. I recently had my door card/trim off to deal with a rather noisy window here's the link for the tutorial http://www.lexls.com/tutorials/body/fdoorpanel.html

I have seen posts on here where the central locking issue has been solved by cleaning the contacts on the door inside of the door handle - search and you should be able to find them. Of course it might also mean doing the same job on the passenger door. Whilst you are in the door, you can have a thorough look at the wiring to the window. You will need to remove the speaker assembly - its self evident but check you've got all the screws out. The assembly itself is extremely well stuck to the door, I prised-up a bit at a time - it feels like you've missed a screw.

When you have completed the cleaning/inspection test everything thoroughly before replacing the door card. I fastened the window switches with a cable tie during that process. Somewhere on this forum is a thread/post about resetting the windows and another about resetting the keyfob all of which I think will be necessary. Whilst you are at it I would relubricate the window moving parts. Apart from a bit of time, WD40 etc, this whole process should not cost anything.

Having satisfied yourself that all is well inside the door, if the problems persist then the fault lies elsewhere. But it must be electrical in nature; all the windows don't pack in at once.

I don't vouch that this will cure any or all of the problems but it is worth doing.

[hydrostat]

sorry, forgot to add, the button on the drivers door to operate the seatbelt height adjust doesnt work either... passenger one works fine.

I have checked all fuses/diodes/relays in fuse boxes (engine bay and under steering wheel)

thanks

Only thing that immediately springs to mind is a broken wire, never had it on a Lexus but it is not uncommon for the wires to wear at the point where they go from the body into the door as obviously this constantly flexes.

Especially on a high mileage vehicle with all of those door open and closes.

[SteveLS400]

sorry, forgot to add, the button on the drivers door to operate the seatbelt height adjust doesnt work either... passenger one works fine.

I have checked all fuses/diodes/relays in fuse boxes (engine bay and under steering wheel)

thanks

Only thing that immediately springs to mind is a broken wire, never had it on a Lexus but it is not uncommon for the wires to wear at the point where they go from the body into the door as obviously this constantly flexes.

Especially on a high mileage vehicle with all of those door open and closes.

I suspect that a broken or trapped wire could be the case and its well worth looking before taking the steps I outlined earlier.

[Wez_LS400]

Hi all,

many thanks for the pointers... i also suspected a bad connection but have had all the fuses/relays/multi-connectors apart and contacts cleaned to no avail a few months back...

HOWEVER!

I used the car on friday gone, started and drove fine, but with the electrical problems outlined above. I didnt use the car on saturday. Come to start it on sunday and the Battery was as dead as a dodo, not even a click from the starter motor and very feint ignition lights.

Started no problems at all with a jump start.... and guess what.... all of my electrics are working again, and have been working fine since sunday.

I have had the drivers side 'kick panel' off and visually checked all wiring and connectors, all seem good, inspected wires through rubber boot into drivers door and again they look like new.

But i am wondering, does the MK4 suffer from any water ingress problems? I only ask as sometimes the car has an odd smell through the blowers, kind of like bad water, and we had a major downpour here on saturday night for a few hours.. could water be getting into electrics somewhere and shorting something out causing my flat Battery, then the electrics dried out and start working again maybe?

Strange one but many thanks for your input.

ALSO, i'm looking for a complete front bumper for my MK4 if anyone can help, preferably in dark metallic blue, mine has recently been damaged beyond repair :(

[SteveLS400]

Hi all,

many thanks for the pointers... i also suspected a bad connection but have had all the fuses/relays/multi-connectors apart and contacts cleaned to no avail a few months back...

HOWEVER!

I used the car on friday gone, started and drove fine, but with the electrical problems outlined above. I didnt use the car on saturday. Come to start it on sunday and the battery was as dead as a dodo, not even a click from the starter motor and very feint ignition lights.

Started no problems at all with a jump start.... and guess what.... all of my electrics are working again, and have been working fine since sunday.

I have had the drivers side 'kick panel' off and visually checked all wiring and connectors, all seem good, inspected wires through rubber boot into drivers door and again they look like new.

But i am wondering, does the MK4 suffer from any water ingress problems? I only ask as sometimes the car has an odd smell through the blowers, kind of like bad water, and we had a major downpour here on saturday night for a few hours.. could water be getting into electrics somewhere and shorting something out causing my flat battery, then the electrics dried out and start working again maybe?

Strange one but many thanks for your input.

ALSO, i'm looking for a complete front bumper for my MK4 if anyone can help, preferably in dark metallic blue, mine has recently been damaged beyond repair :(

Hi Wez

most interesting.

It is possible that the drain holes (under the trim where the wipers are) are bunged up thereby collecting water which eventually becomes stagnant. I have not had this problem but I'm sure you will be able to remove the trim. BUT make absolutely sure you know the EXACT position of the wiper arms, take photos with them parked and at rest and at the top of their travel BEFORE you remove them and double check their operation after refitting. As I posted a while ago, the nice windscreen man didnt do this with mine and they didnt work.

Talking of water ingress, its worth checking the drain holes in the doors and in the moon roof. It might be worth looking in the spare wheel well for signs also.

In my earlier replies I forgot to mention an earth fault. Make sure the earth connections are good although I'm assuming you already have. Have you had the Battery conditon checked? And what about the alternator charging rate?

[Wez_LS400]

Hi,

Thanks for your reply!

I have not had chance to check the drain holes in the wiper panel... job for monday night! Cheers.

A quick inspection around the boot seems dry, but again i will remove some trim whilst my hands are dirty with the above task.

The Battery is 2yrs old and alternator gives a healthy charge with engine running. When the Battery died, it did it basically overnight, so i guess something is pulling power when it shouldnt be.

It did play up again yesterday, locked vehicle fine, upon returning it would not open with button on key, so used key in lock, opearated all central locking fine, then opened the drivers door and alarm started sounding, no matter what i did i couldnt get it to stop (tried locking/unlocking, even started the engine with alarm still sounding) eventually it stopped of its own accord after a minute-ish.

But now my buttons on my keyfob dont work - but everything else is fine still....

Is there a key programming guide? I have the 3 button keys (lock/unlock/boot)... i have tried the search but it brings up many pages of unrealted topics (unless i'm not using it correctly!?)

Many thanks again!

[SteveLS400]

Hi,

Thanks for your reply!

Is there a key programming guide? I have the 3 button keys (lock/unlock/boot)... i have tried the search but it brings up many pages of unrealted topics (unless i'm not using it correctly!?)

Many thanks again!

Hi again

I searched "remote" and got 8 pages, many of which were helpful. This one is the one that may be most useful

http://www.lexusownersclub.co.uk/forum/index.php?showtopic=59617&st=0&p=660659&hl=remote&fromsearch=1entry660659

I cant remember if this mentions about not storing metal objects, mobiles etc in the armrest, but the advice is not to do so.

[Wez_LS400]

Hi again,

thanks for those links, i've tried all of the procedures, none of the m will get my remote central locking back :(

Car has behaved itself lately apart from the C/L not working.

I still desperately need a front bumper though - i'm driving around with 'gaffer tape' covering the broken sharp edges... not a good look!

[steve2006]

Hi again,

thanks for those links, i've tried all of the procedures, none of the m will get my remote central locking back :(

Car has behaved itself lately apart from the C/L not working.

I still desperately need a front bumper though - i'm driving around with 'gaffer tape' covering the broken sharp edges... not a good look!

One thing nobody else has mentioned are the door courtesy light switches,they do become erratic after a few years but can normally be sorted by removing them (don't loose the wire inside the bodywork!!) and giving them a good clean with switch cleaner then spray with WD40 working them in and out a few times to distribute the liquid.

As for the bumper have you PMd Maurice on this forum his username is benfur I dont know about the later models but he normally has a good stock of spares all I might add at a very reasonable prices!

[Wez_LS400]

Where are the door pin switches.... i had thought these may be the problem, I looked for them but oddly enough couldnt spot any!?

Thought there may be some sort of magnetic switch in the door instead...

and thanks for the tip about maurice, i did ring him, he sold his only one just a few days ago :(

cheers

[SteveLS400]

Hi Wez

I haven't time to plough through them, but on fleabay there are ususally a few breakers advertising. Try contacting them for the bumper. Also, I have found this site to be helpful

http://www.247spares.co.uk/

If you've not used them before, you tell them what you are after and you get emails from breakers giving you a price.

[Wez_LS400]

cheers, i check eBay almost daily, and i think most of the breakers are sick of me emailing them now lol.

theres a few MK4s breaking at the moment, but they all have front bumper damage :(

i did look into those parts finders, but most were charging £1.50 to £5.00 per qoute sent, however that one you have linked to seems free.... off to sort it out now, many thanks!

[simontaylor]

or get some "same colour" gaffer tape for an extended interim solution. I dont know what the damage is like, or how big, maybe put a 'stripe' of tape in a wrap around sytle across the bumpre.

Good luck.

Maybe ask your local Lexus dealer to inform you of the next MK-IV they get in for part exchange. It may be worth buying???