Electrical Connection to Rear Differential Question

[Nunapitchuk]

There is some kind of sensor or other device on my rear differential. It has a two-wire electrical connection to it.

My questions are: What is it? What does it do? How does it work? And is it something that might need replaced after 160K miles?

[fixkick]

welcome , Cowpoke.

I'm not sure what car you have, or year?
but many have RWAL
type that in my search box, kickfix.com

thats the rear wheel antil lock break sensor

here we go
http://search.freefind.com/find.html?si=...query=rwal

see?

There is some kind of sensor or other device on my rear differential. It has a two-wire electrical connection to it.

My questions are: What is it? What does it do? How does it work? And is it something that might need replaced after 160K miles?

[Nunapitchuk]

Thanks. I found a page describing the RWAL.
My vehicle is non-ABS so I was not expecting any kind of antilocking system.
So that is just a speed sensor in my rear differential.
Do RWAL sensors wear out and need changed after 20 years or are they usually pretty stable for the long term?

[fixkick]

abs in not Rwal
rwal is early experimental crude abs (NO FRONT CONTROLS)
if you car has no Rwal controller at left toe
and no dump valve on master cylinder
then those were removed
or someone put an RWAL axle in your car,
abs is 1996 thing, actually here. and was optional for many years.


Some years in place of RWAL have this
part 20
this is load measuring, device, that make rear brakes stronger the more load added to rear of car.
http://www.fixkick.com/brakes/96-98nonABS.jpg

the rear axle sensor , just gets dirty, cleaning fixes most. if wrong at all
the RWAL box has flash codes,
my page show how to get those codes.
and if no bad codes, that senor is ok
the Brake lamp in cluter glows for when RWAL is unhappy, (and handbrake on and low master cylinder levels)

[Nunapitchuk]

It looks like original equipment. Here is a photo of the RWAL sensor and the brake hydraulic parts that I removed. So it looks like an original installed RWAL system, right? I don't know the names of all the parts yet.

Just curious, how does that sensor work? Is it an open/close switch that is triggered by some condition in the rear differential?

[fixkick]

works just like abs, but just stops rear axle from slipping
its tachometer sensor. just like a crank sensor, or vss sensor or,modern abs sensor.
its purpose is to stop dangerous, over steer on ice (swapping ends)
if it sees the axle rpm drop too fast , it knows the brakse, are locked up
and then activates the dump valve fast to lower rear brake line pressure.,ending skid on ice or dirt.
cheers.

it just and rpm sensor, no more,

cheers

It looks like original equipment. Here is a photo of the RWAL sensor and the brake hydraulic parts that I removed. So it looks like an original installed RWAL system, right? I don't know the names of all the parts yet.

Just curious, how does that sensor work? Is it an open/close switch that is triggered by some condition in the rear differential?

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NICE work BTW !!!

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its very simple, no?
just one dump valve and one sensor.
but could save a life, i guess.
one way to test it would be on ice parking lot or on wet grass
try to look up brakes.
fronts my but not rear.
cross fingers.