Disabling your washer level alarm / What kind of washer level sensor is this?

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BRIANGEE

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Does anyone really need a computer ding-donging them because of low washer fluid? I don't - and I was going to "fix" my washer level float so that it never comes on again until I realized it's not a float at all and is some sort of sensor. I pulled the wiring diagrams to see what I need to do to get the computer to think that the reservoir is always full and see that it's some type of resistor but after playing with it for a while I'm still more puzzled than ever. See the pictures below.

Here's Ford's description of the fluid indicator:

Low Washer Fluid Indicator - Expedition

The instrument cluster is hardwired to the low washer fluid switch. The low washer fluid switch closes
when the washer fluid level indicated is approximately 1/3 full, providing a ground to the instrument
cluster and turning on the low washer fluid indicator. When the washer fluid is above the low level, the
low washer fluid switch opens and removes the ground to the instrument cluster and the low washer
fluid indicator turns off.


So, apparently just unplugging the sensor would accomplish the same thing as the switch never grounding out and the computer will always see the full reference voltage and never bug you about the fluid level. In messing around with this sensor the reference voltage was 11.3 volts (battery is at 12.6v) which I was really shocked to see. This is the voltage at the connector unplugged. Plugged in I could not get any variations in voltage by back probing and adjusting light levels or temperatures. I poked and prodded plugged in, and unplugged and resistance and voltage never budged. Now I suppose I could have a bad sensor but I'm wondering what the heck type of sensor this is and how does it determine the level of fluid? In case you've never seen this before it doesn't insert at all into your reservoir - it just simply attaches to the outside of your tank with the black sensor part facing the plastic.

Any ideas?
IMG_20180614_132542060.jpg IMG_20180614_133851851_BURST001.jpg
 

Prince_Polaris

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Hey, that's the thingy I'm having fixed tomorrow! They're gonna replace the whole tank so I'll have to come back and tell y'all if it fixed it or not, because yes, being told my fluid is low every time I start the car is immensely annoying...



EDIT: Oh dang I realized what you were asking! I'd bet money that the sensor you're holding there is an Infrared sensor! Somewhat like a really basic camera, it's designed to "see" through the wall of the tank and determine how much fluid is inside!

Hmm... that would explain why they fail, as the plastic of your tank gets old and less clear, I bet the sensor has a harder time seeing whether there's fluid in front of it or just some sort of dirt.
 
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BRIANGEE

BRIANGEE

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Prince, if you can live without it just unplug it - that's the moral of the story ;-)

I don't want it or need it so bye-bye it goes.

But an infrared sensor - now that would explain why I could not test it. You might be on to something but this thing is pretty opaque and solid looking - I looked at some IR sensors online and this looks different.
 
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Prince_Polaris

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Prince, if you can live without it just unplug it - that's the moral of the story ;-)

I don't want it or need it so bye-bye it goes.

But an infrared sensor - now that would explain why I could not test it. You might be on to something but this thing is pretty opaque and solid looking - I looked at some IR sensors online and this looks different.

Well, the car is from 2003, so perhaps it's an older sensor? Hmm.... well, I was gonna say that old TVs have similar black screens over their IR transmitters/recievers but that's different tech, I think... if it's not specifically an IR reciever, it's definately something involving sight, if it's only on the outside of the tank.
 

Prince_Polaris

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Okay, update! I just got the car back from the mechanic, and you know how they fixed my washer sensor? With a brand new tank! And this one is actually clean, and mostly clear, making it super easy for me, and the washer fluid sensor, to see how much is inside of it!

So, I think the sensor is meant for "seeing" the fluid level, which means either a cleaned tank or new tank is how you're meant to fix it.
 
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BRIANGEE

BRIANGEE

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My fix is cheaper: Unplug it. And with the added benefit of no more ding **** sounds! LOL

But to each his own... how much did you fork out for the mechanic to swap the tank? You know the thing is only held on by several bolts, unplug the washer pump hoses and electrical connectors and out she comes.
 

khooddad

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My 2012 seems to have a different switch. BTW the pump and switch are easily accessible after taking of the passenger headlight with 2 100 mm bolts
 

whtbronco

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I'd unplug that sucker too. I really dislike all the alarms/notifications and disable them whenever I can.

It used to be so easy to simply remove the chime module from a vehicle and the problem was effectively solved. Not the case anymore.
 

JamaicaJoe

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EDIT SOLVED!!!! The sensor is magnetic! There is a tiny float and magnet inside the tank and you can check this with a neodymium magnet placed in the pocket where the green sensor normally goes. If the water is low, the magnets will attract (or repel).

I think my problem is that the outlet lines are leaking thus the tank usually is too low. Now that I understand the mechanism, it should be an easy fix. I assume the float does not have a slow leak, in which case a new tank would definately be required.

BUMP!!! I am having same problem with the sensor. In fact i removed the entire tank today because the battery needs replacing and I wanted to inspect for any rust under the tray and fender wall. Thankfully none.

In any event I have that green sensor as well and I am puzzled as to how it actually works. Inside the tank there is a vertical rectangular column for water to stand. I expected there would be a float and magnet but I don't see anything like that rattling around in the tank. Has anyone a clue as to how it is supposed to work?
 
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