Mvinhie

I got a lexus es300 1997. I just got this car and i dont know why the fan run all the time when i turn on my car. I try to pull out the green coolant temp sensor or called a fan switch on the top. But that method doesnt work and i also pulled out the gray connector near it but it doesnt do me any good. I already pull out all the fuse. When i pull it it turn off. So what am i doing wrong.

PuReChaos

Do the fans run when the engine is off but the key is in the on position? If so, just recently had a friends car have a similar problem and it wound up being one of the water temperature switches was bad causing the fans to be running at high speed at all times.

Lets see if I understood what you've done so far. You've checked the switch near the top of the engine block (or so it appears in the diagram labeled W5), how about trying other water temperature switch (W4) located in the front of the radiator. I'd start with disconnecting the harness to each one at a time and see if either water temp switch is bad. They have grey wiring harnesses, and W4 has 2 pins and W5 has 1 pin just for reference.

I'm only suggesting this as I experienced a similar problem recently and that wound up being the cause, if this doesn't help you out, you could always use a digital multimeter to check the switches and relays which would be my best guess as to what the problem is. I can post the electrical wiring diagram if needed.

Mvinhie

Hmm is the w5 suppose to be a engine coolant temperature switch? And w4 i dont have it on my car

Mvinhie

I took my radiator out yestsrday but i dont see no ect switch on there. Is there suppose to be one? I see a drain plug and next to it they have this plastic cap i can twist. I was wondering if something suppose to go there.

Mvinhie

The one i circle in the red is there suppose to be a engine coolant temperature switch number 2 going in there? i can't seem to find where it located beside the coolant temperature switch number 1 i know it located on the left side top

Mvinhie

can anybody help?

Sprey

From your last picture that just looks like a extra plug to let out the water from the radiator?.

Id say you've got a bad temperature sensor.

I had a similar problem not long ago.

Fans ran full speed constantly.
Replaced the sensor and back to normal

Tho my engine is the 3vz-fe but should be roughly similar.

Check the sensor on the pipe that comes off the thermostat housing right where the cambelt is.
( if theres one on your car not sure about the difference between my es300 and yours.

Mvinhie

Pulled out the no.2 ect switch it didn't turn off the fan.... Im guessing i need a no.1 ect switch since i don't even have one installed on it. Also do anyone know where i can get a no.1 ect switch wire connector? ive been trying to search for it but nobody sale it online...

PuReChaos

There is only one engine coolant temperature sensor as far as I know. They are different from water temperature sensors which I highlighted in the previous picture, both should have grey wiring harnesses. The engine coolant temperature sensor doesn't even play a role in fans running according to the wiring diagram.

From your picture it looks like you're on the wrong side ( I could be wrong about this, please correct me if I am). It should be the front driver side closest to the bumper/grill.

I would be willing to post the documents (EWD/electrical wiring routing) I'm looking at if that would help you.

Mvinhie

On the diagram i look there is two engine coolant temperature switch. One under the radiator by the drain plug and one on the left side top near the engine and also the water temperature sensor is near the engine coolant temperature switch too. I try your solution pull out the plug from the water temperature sensor and engine coolant temperature switch neither stop it from running the fan. I pulled out the relay it stop though but then again somebody change my radiator a while back and i don't see it have any engine coolant temperature switch and it also missing a engine coolant temperature switch wire. Could that be the problem why my fan keep running?

Mvinhie

do you know where i can buy a engine coolant temperature switch wire?