Weird headlights

[MrChemist]

Today, my 2010 RX450H suddenly started turning on its headlights some minutes after stopping, leaving and locking the car. When running, they behave normally. It's just 10 or so minutes after...

I thought it was "AUTO" playing up, but it does this when the lights are turned right off. Drove it up and down the road, no change. I remember the manual saying that the car should make noises even after it's turned off, but it's not noises... I wonder whether it's something wet or confused by rain, because here it hasn't stopped piddling down since October. I haven't been through any standing water, barely even any puddles, they tend not to gather on Sheffield hills.

I can't get it in at the dealer before the end of next week, so I disconnected the Battery because even LEDs will flatten the Battery in time (they could be a symptom of something else that is also consuming power), nor do I need a steady trickle of my lovely neighbours coming to tell me I've left the lights on. Maybe being off for a few days will reset whatever it is. I did try to disconnect the bulbs, but there are so many awkward, sharp bits in there, I can't work out where to press each connector to undo them, and I have bad arthritis in both thumbs.

(At least it's secure, I could lock each door individually, then the driver's door with the key. Yes, now I have to climb into the boot to unlock it, but better than leaving it unlocked.)

So, any thoughts?

[Herbie]

No idea what's wrong but instead of going to the dealer I strongly suggest finding a proper auto-electrician to sort it out.

[LexusDave]

I can remember from my days of owning an IS200 that a lot of owners were experiencing this same problem although I didn’t have the problem myself. The problem was being caused by water leaking through the scuttle, below the windscreen where a cable passes through and the water would drip onto the fuse board and relays. So I think your link with the wet weather is probably on the right lines. The cure was to locate the problem and silicone it, and then to try to dry out the fuses and relays.