As far as I know, the rain sensors are speed senititive, not directional senititive.

 

The weird things happened again today, 20 mins after the huge pouring rain for 7 miles today afternoon on Massachusetts Turnpike.

I ususally leave my sensing wipers ON. After 20-30 miles good weather, it's dribbling again, and getting bigger. But, my wipers weren't moving no matter how I adjusted the sensor. Finally, I cancelled the sensing wiper, then moved back. It started to work again.

 

Thats pretty common with auto wipers in many cars, it falls asleep. I usually tap the sensor or turn it off and on to wake it up.

 

Understood. Good to know. Thanks.

 

2007 RX350. My rain sensor worked fine for the first 2 years. Last December (2009) I went back to the dealer for "hose recall". On the way out of the parking lot, I adjusted the rear view mirror and the wipers started running. The service people decided to disconnect the system and I was told they would order the replacement part. Went back for another service last week, was told no one ordered the parts for us. Good move Lexus...
The sensor is behind the rear mirror.

 

I don't remember having to do this on my 2004 LS430 at all, but with the RX350 I have to do this every now and then. I do think there's an issue with the sensor on the RX.

 

It's possible you are turning into the direction the rain is coming from so the system thinks it is raining harder and adjusts accordingly