I just changed mine last night. It was chattering.

 

I rarely ever use my rear wiper. I like having it there, but I never want to use it. The only scenario(s) where I will use it is if it is pouring down rain and I am on the highway (greatly increases rearward visibly) or if there is a layer of condensation on the glass from sitting overnight. Then again, I don't use it every time one of those scenarios occur.

Also, when I do use it, I always have it on the intermittent mode.

 

Interesting question, Daddy-O.......I bought the 99 for SHE WHO MUST BE OBEYED in May of 98; I have PIAA silicones on the front which seems to have remedied the RX's appetite for new wiper blades every 2-3 months (driver's side very quick to develop chattering), but have never replaced the rear blade. Tho always on "intermittent" when used, you'd have to think that it's gotten a fair amount of use in over 4.5 years. Still no chattering or streaking tho; wish SHE would take the hint...........

 

Here's something I don't understand (another one): most SUV's, like the RX, have a rear window that is almost vertical-rain water should just drop off. yet, i think just about all suv's come w/ a rear window wiper. on the other hand, sedans/cars....all of the other Lexus cars that aren't suv's don't come w/ a rear wiper (unless you get a cold weather package or its japan spec), even though all sedan rear windows are less vertical and therefore, should have a harder time just "dropping off" water. someone please, correct me if im wrong somewhere.

 

There's a low pressure area created behind the the horizontal surface of the roof. It's caused by the abrupt drop off (tailgate). It causes anything suspended in the air to cling and stick to the rearend...Rain when wet and dust when dry. It's a common trait in all boxy station wagon, van and SUV designs, hence the rear wiper.

Roof air deflectors help to disturb the air pattern in an attempt to keep the rearend clean.

 

If you ever park your car outside in the snow and then go driving without cleaning the snow off your roof, you'll see why the rear wiper comes in handy.

The way the air flows over the top of your car creates the low pressure area daddy-o explained. This low pressure sucks the powdered snow down (and sometimes up from the snow/sand kicked up from the tires) and it hits your rear window and clings. Im kind of glad I have it.

In other news, I was driving my GF's new Altima 3.5 SE the other day and it was drizzling. The rain drops collected on the rear window and annoyed the hell out of me. I really needed a rear window wiper.

 

I've been using the rear wiper extensively because of the poor weather and road dirt (salt) that gets on everything, especially the back of the RX.

Yes, sorry, but I must take the RX out in that terrible stuff.

Alas, the wiper does need replacing (probably original from 99) but what is the coolest ever is the washer that works in conjunction with the wiper to help improve the visibility through the rear window after the salt starts to dry.