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Headlights Staying On When Car Is Off

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having your windscreen changed, IS the cause of your problem, the screen has not been installed correctly, and water is getting in at the bottom and running down into the drivers side fuse and relay box causing a short in the relay

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having your windscreen changed, IS the cause of your problem, the screen has not been installed correctly, and water is getting in at the bottom and running down into the drivers side fuse and relay box causing a short in the relay

I had my windscreen changed last year and recently suffered the same problem however am not convinced in my case it was due to the windscreen. I did indeed find some damp in one of the sockets in the fuse board and after drying out it seems to have cured the problem. I then removed the scuttle tray and directed water all around the windscreen so it ended up in the space below the wiper motor. This tested the bulkhead drain holes which were ok and I then checked for any water at the bulkhead wiring grommet above the accelerator pedal and around the fuse box wiring - found none. The windscreen glass protrudes about an inch below the sealant level and as water doesn't tend to travel uphill it can't get in that way.

As the scuttle tray has holes in it water can easily enter there but should simply go out through the drain holes, worth checking they are not blocked. This was two weeks ago and since then we have had heavy rain and the problem hasn't reacurred. So how did the water get into the socket - I'm thinking possibly from damp and condensation rising from the drivers footwell - can't see any other way.

Also, a few people have reported this same problem and have never had their windscreen replaced.

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check both side fuse boxes and all connectors (including all pins),seriously i had the same problem twice and after 3 days of checking every single pin on every connector the second time i found 2 plugs on the drivers side fuse board completely corroded and had to get a part wireing loom for that connector,and on the passenger side i found 3 pins that were going the same way but managed to clean them up with a small file and electrical cleaner.

also check to see if your theft ecu is ok and hasnt burnt out on the is located underneath the knee guard just behind the ignition ring

any probs just pm me and ill try to help you out all i can

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I thought I'd hijack this thread as I've had similar issues - I've posted in the main (12 page) 'Headlights staying on post' where there's more information.

I haven't had my windscreen replaced but experienced problems with the inside of the car misting up - probably due to blocked sunroof drain holes I think.

I unplugged both connectors from the theft deterrant ecu but still my relay buzzed away - I would have expected that to stop if it was the issue. It seems the problem is between the light relay and the fuse box at the side of the driver/passenger footwell.

Does anyone have a diagram which shows what the connecters in each footwell are for - I know I'm looking for a headlight related wire so it would be good to have a guide about which ones are which.

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The mechanic has had a look at the faults you mention and cannot find any moisture getting in. What's more is that the problem of the headlights staying on has gone away. It has been replaced by a different problem... when I put the headlights on "auto" only the side lights come on - no headlights. Any ideas????

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I have read some of the forum posts on this site, and my problem is this; when I turn my ignition off my headlights come on! they are the Xenon type (they were fitted with the car and are factory fit).

When the engine is running everything is fine but as soon as the ignition is off the headlight lights remain on (no other lights at all just the two headlights) and there is nothing I can do about it. I have had the stalks checked and the relay switch checked, and no errors are reported on the diagnostics machine.

I have had to take the relay switch out in order to cut the power to the headlights so the Battery doesn't drain.

I have spoken to Lexus Liverpool, and they state that although this is not a common problem, they have dealt with it before with this model. They stated that the fuse board near to the drivers foot well needs replacing and the ECU. This is probably due to water ingress from the windscreen area, which has corroded the fuse board. I have had a brief look and there appears to be no water in the fuse board / foot well area, even after pulling all of the trim out and having a good look, even drying it for an hour or so with a hair dryer !

Why do both parts need to be changed? Can you change the fuse board and not the ECU, or do they have to be changed together ?

The quote today was as follows :

Block Junction (fuse board) L82731-53011 £287.52

ECU L89220-53420 £241.23

2 HOURS LABOUR £160.00

TOTAL £688.75

As you can imagine I couldn't believe the price, and had to be carried out of the garage !

Does anyone on this forum know of any hints / tips solutions etc or decent garages (in the Liverpool ish area) were this problem can be looked at for cheaper etc..

Thanks in advance for viewing this post etc....


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