I have a 2007 RX350 2WD. 2 days ago while raining, the wipers stopped in the full up position when my girlfriend was driving. I read up and found that this car has a relay (looks like a small computer) behind the glovebox. So I got a used one for about $60 locally and plugged it in and it worked for about 3 seconds and then stopped working. I am wondering if it's coincidental that it stopped working as soon as power was applied to the circuit or if it was bad already. Who knows how long it was sitting on the shelf of the place I got it from. A new one is about $300 from local Lexus dealer and it's not that much cheaper anywhere else if you can even find it.

I am wondering if anybody has a wiring diagram I can check out and if somebody knows of a place where perhaps it is cheaper than about $300.

 

The box behind the glovebox is not a relay, it is a small computer, the wiper ECU. But maybe the wiper motor itself is bad. When the wipers are supposed to be running, try tapping on the wiper motor and see if it will start running. If it starts running, the motor is bad.

 

I only said relay because the part is labeled as a relay. But yeah it's basically a small computer. Haven't tried messing with the wiper motor. Didn't think that would be the issue.

 

wow ecu ffor wipers?Is this a lexus thing? hope highlanders do not have one

 

If they do, I think it's a different part number because when you run the part number, it is compatible with a few other Lexus models as well. But when I called Lexus earlier in the week they said it was $286 from them. I wouldn't be surprised if every newer vehicle is implementing this new technology they think is superior.

 

the Wiper ECU is used if the vehicle has the rain sensor option. So if your Highlander has the rain sensing wipers, you have a wiper ECU. Whether it is the same unit as the Lexus, I don't know, but it has a good chance of being the same thing.

 

thanks.
no rain sensor on my car.
so it wont break either

all the Lexus complexity does what? turn on the wipers?

 

The auto rain sensor is one more click of the wiper switch. You have intermittent and constant, we have those plus rain sensor. The wiper ECU electrically sits between the switch in the steering column and the wiper motor. While all switch functions go through the wiper ECU, the ECU is needed for the additional input wires from the windshield which serves as a secondary windshield wiper switch.

Myself, I have learned to like this. I leave the steering column switch in the auto rain sensor position and I don't have to worry about. The wipers work as needed, intermittent or constant. The intermittent is only as needed. If the windshield is cleared with one sweep, the wipers shut off.

 

So I finally got the new wiper ECU from Lexus new, and it didn't fix this issue. I don't know why the wiper motor being bad would cause the issue I'm having. Currently, the wipers are stuck in the center of the windshield. When I move the stick on the column, I get nothing. The rear wiper works as well as the fluid comes out both front and back. Could the switch in the steering column be bad? If the motor was bad it would still try to work in one of the settings I thought or maybe just fall down to the rest position behind the hood.

Any ideas? I don't have a nice gauge for checking codes of any kind. I have 2 code readers that are generic that will read check engine codes and then my aeeoforce for my F350 but it's specific to my truck so it won't read much on the Lexus.

 

The wiper motor is bad. There are electrical contacts inside the motor to allow the motor to complete one full wipe of the windshield and return to the park position. When the contacts go bad, the wiper arms stop somewhere in the middle and that's it.

You can use your voltmeter to double check that the wiper switch is sending power to the control module, but I think you will find that the voltage is at the control module.

 

I have a 2005 rx300 right hand drive where is the wiper Ecu located

 

Hi Dano999,
Welcome to club lexus!

I don't know about right hand drive but maybe it is located behind the glovebox up high in the dash(but on other side).
Let me know if this helps plz.

See #A29 in drawing.

 

Still not found wiper ecu on. My right hand drive rx

 

Did you ever find the solution to your wiper problem?

 

I swore I posted here what had happened, so i apologize as i know thatbis frustrating when people dont follow up.

I ended up replacing the stick on the steering wheel and that fixed it. I was thinking of doing the wiper motor but somehow the stick for the wiper blades was the issue I was having. I also sold the RX350 not long after this because i got tired of fixing it all the damn time.
Wife now has a new gen 4Runner trd pro. Much better vehicle.haha