where is the sensor in the rear you need to clean to make this stupid light go out!!!
ABS still works but now the light is on all the time!

 

Make sure you dont have any burnt out taillight bulbs before you go tearing your hair out. One of the third brake light bulbs being bad will make the inop light come on and a scan wont tell you what its from.

 

You know I had the same problem and I think it had something to do with a wire being caught under the center console. After I replace the center console it went away. I had CONSTANT ABS INOP and EBRAKE lights going on until then. Haven't seen them for months now. Weird.

 

nope no bulbs out in the back
i just replaced a few and 1 that burnt out in the 3rd brake light.

 

The rear ABS sensor is plugged in on top of the differential housing of the rearend. The sensor itself is sort of "inside" the rearend. There is a ring similar to a flex plate around the circumference of your zexel/gm/posi (whichever) unit that resembles the circumference of your flywheel. The sensor button sits on these teeth as it rotates or is static. This lets the computer know if the tires have ceased rotation while braking. The reluctor ring will wear out sometimes, causing an ABS INOP error, but that is rare.

Did you replace spark plug wires lately? If you run a spark plug wire too close to the ABS wiring that goes to the rear, it can cause interference.

If not, try ohming the wiring from the front of car to the rear, and see if you have any "opens." Also, check the plugs at the rearend and at the connector that is located directly in front of the rearend on the sheetmetal. Sometimes these will work loose if the rear sees a lot of up and down motion from bumpy roads and such.