Rain-Sensing Wiper Operation

[eugene.s]

Rain-sensing wiper operation (when you move the knob one step down from the normal position) gets me crazy. My GX470 was absolutely sensitive to my regulating the sensor sensitivity (via the ring on the knob).

On LX570, adjusting the sensitivity ring seems to result in nothing. The sensor doesn't seems to capture any water drops at all; and rain-sensing function on LX works maybe 10 times worse than on GX.

Tried all customization options but found nothing so far (save for the rear window wiper regimes).

Any advice how to make the rain-sensing sensor more sensitive?

[Ashron]

My auto sensor died. It worked great beforehand and adjustment sensitivity was excellent. Had it replaced by dealer. Now sensitivity is poor and changing the sensitivity knob makes no difference to the sinsitivity of the system at all. Its as if the sensitivity knob doesn't work at all.

[eugene.s]

Ashron, many thanks. Any advice how to check this sensor or where it's located?

[Ashron]

No I don't know where its at. But since I just had the auto wiper system fixed, I was going to take it back to the dealer.

I'll keep you posted.

[GDixon]

I think the sensor is located near the rear-view mirror where it glues to the windshield. At least that is where the RX sensor is located.

Try spraying some water on the area when the auto-sensor is active (engine on, switch selected). That should diagnose whether it works or not.

[pj8708]

The rain sensor is located directly behind the inside front rear mirror. It is stuck to the winshield with a pretty substantial adhesive. As you two have said earlier, it can be kind of difficult to get it "tuned in" for your particular needs. One quirk I've noticed is when you get in and start the car, and you had all ready set the wiper interval setting to only come on when it begins to sprinkle, as you drive off and it does start to come down with a light sprinkle, the wipers won't come on. Even though their set to do so. I've had to pull the whole wiper control stalk down another notch to get things going.

This is only on rare occasions. Other than that I love the feature.

Everthing you are asking about is in your Owners Manual. However, there are some differances if your Lexus has a Navigation or not. I'm posting a link for Lexus Corporate Customer Service. They can help with your tech questions and an Owners Manual if you need one.

I hope this has been of some help?

Paul

http://www.lexus.com/contact/index.html

[eugene.s]

Thanks to All for the info. The auto-wiper actually works, what doesn't appear to work is its sensitivity adjustment (via the ring on the knob). I'll try Paul's link but well expect the answer "visit the dealer" (no Lexus dealers in my place). So, anyone who knows how to "regulate" the sensitivity adjustment (i.e. to anchor the knob ring to start from some "more sensitive than usual" regime) or how to isolate what doesn't work (e.g. the sensor itself or the wires or a glitch in the onboard computer settings, etc.), please kindly post a solution here.

[Ashron]

I had the dealer fix my "sensitivity Knob" recently. It works great. (as new). No charge either since they previously replaced the rain sensor. (I guess they forgot to hook-up or program the sensitivity sensor.

[eugene.s]

For those who have the same problem. If the auto wiper does work in principle, but the sensitivity knob cannot adjust the sensitivity. Which means that the rain sensor itself works, only the sensitivity cannot be changed.

From my research, the problem must be in the tape between the windshield and the rain sensor. When not being attached properly (or when being even slightly detached e.g. due to improper installation originally), it leads to unavailability to adjust the sensitivity.

I've ordered a replacement part and will try it over my May holidays. I will report.

[eugene.s]

The problem is solved:

(edit 13 May '14: some tweaks added to simply the process, following the Russian Lexus forum feedback on a similar post)

NB: If you access this forum from a non-US IP, you may fail to download pdf attachments. Request access in this thread or contact the forum support.

(1) Test the rain sensor operation (the testing manual is here: Inspection.pdf)

Note that testing if the sensitivity adjustment (via the ring knob) takes effect requires driving at the speed above 20mph.

In my case, the testing was not necessary as everything had been tested while driving in the rain: the rain sensor worked but the sensitivity adjustment didn't.

(2) So, if the sensor works, the root cause of the problem must be in some other component of the system (the components are explained here Components.pdf)

I suspected the rain sensor tape. A visual inspection revealed obvious defects of the tape

.

So, am due to replace the tape.

(3) It costs ~$20 and you can check the part number for your particular car through, e.g. this site (enter your car's VIN and then search for "rain sensor tape"). This e-shop from the States offers discounts for this forum's members (as I am in Russia, I bought the tape from a local shop).

(4) Now let's remove the rain sensor so that we can replace the tape. The removal manual is here:

Removal.pdf

When the sensor is removed, take out the old tape. It will likely stay on the windshield - ref. the pic immediately below, where the tape remains on the windshield. On that pic, you also clearly see the squared area on the windshield where the new tape (once attached to the removed sensor first) is due to be applied.

Take out the old tape and clean this area on the windshield with any grease remover (while you do the next steps, this will allow a few minutes to let it dry).

The dismounted rain sensor and the removed old tape on top of it is shown on the picture here

(5) Now let's anti-grease the area on the rain sensor itself, where the tape is to be attached (after that, let's wait a couple of mins to let the surface dry before applying the new tape). This area on the sensor, to which you need to apply the new tape, is clearly indicated (ref. the squared area with rainbow blotches on the sensor)

anyway, check the installation manual to be sure.

Installation.pdf

Then apply the new tape therein (the tape is first applied to the removed sensor). Be careful to avoid any air bulbs.

(6) Then, assemble the system back. You basically just need to put the sensor (with the new tape attached) to the same area which you identified in step (4) above. The re-assembling manual is here.

Installation.pdf

The whole procedure took me maybe 15 mins. The most difficult part was to install the tape to the removed rain sensor exactly where it belongs. And not to leave any air bulbs. This was my first experience and I only succeeded from the 5th attempt (retrying is not a problem, only make sure not to leave any fingerprints on the tape - these are oily and may deteriorate its performance). Though, when re-assembling the system (i.e. when putting the rain sensor back to the windshield) you cannot control air bulbs between the tape and the windshield. I allowed one small bulb, but this is not a problem.

The auto rain sensor now works as due and the sensitivity adjustment knob works perfect as well.

Good luck to you and if any questions, feel free to ask (that's what this forum is designed for!)

[GDixon]

WOW! You were really serious about this issue. Good for you.

Thanks for posting back all of the valuable information to guide others that encounter this problem.

Well done!

[eugene.s]

GDixon, I have no choice rather than doing everything on my own. Have no Lexus/Toyota dealers in my remote place!

[pj8708]

GDixon, I have no choice rather than doing everything on my own. Have no Lexus/Toyota dealers in my remote place!

As a follow up to your note up above, and for all of you who like or need to do your repairs your self ,I've placed a link to a Toyota and Lexus website called TID for short. It is an amazing collection of parts and diagrams for all mechanical assemblys and all electrical systems and wiring diagrams.

It also has all Technical Service Bulletins and recall information put out by Lexus.

This a terrific source of knowledge. The catch is that you pay for the amount of time you want to use the site. The smallest block of time is 2 days for $15 dollars. It goes on to by the week, month, year. A year is between $1,000 and $1200. I find that I can learn and trouble shoot a lot over a 2 day period.

Paul

https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&SMENC=ISO-8859-1&SMLOCALE=US-EN&SMAUTHREASON=0&SMAGENTNAME=%24SM%24mT%252bGLraBu9CwUVnZg4mEDzB2kysT90hgbwsWgdZzNOc%253d&TARGET=%24SM%24https%3A%2F%2Ftechinfo.toyota.com%2F

[strong1993]

Take it to the dealer. I had my windshield replaced and the shop didn't replace whatever goes between the sensor and the windshield. When they replaced that part, it worked perfectly. Before they replaced it, the wipers would wipe during sunny days.

For some reason I didn't see you resolved...

Edited December 20, 2014 by strong1993

[bbctooman]

My 2013 570 sensor is located in the rear view mirror assembly facing the windshield. I also had a problem and dealer fixed it with a "tightening" of the rear view to the window? Subsequently, I did have to get a new windshield due to AZ stone kick ups and watched the tech put in the "gel pack" that does the sensing in the rear view mirror assembly.

B Berg