Ok here we go. I bought my father inlaws 1998 blazer 4x4 after he died. There is no abs light on in the dash but at every stop the abs kicks in and makes it stop like you are on ice oon a dry road. With no light on will there be a code? I suspect abs wheel sensor butt dont know how to tell which one. Should there be an air gap setting? If so what is it? I looked and nothing appears unplugged anywhere. No apparent broken wires under there. Gotta be wheel sensor. Any help suggestions will be appreciated. Thanks guys.

 

It could be either of the sensors. The Airgap is obviously critical for the proximity type probes, but the direct way to ensure that the sensor is set properly is to measure the mV-AC output from the sensor while turning the hub. You cannot directly measure the airgap on the 98+ integrated hub/sensor design.

This thread will help you get things operating properly once again:
Brakes - Low Speed (below 5 MPH) ABS Activation

 

That sounds like the ticket. Looks like a project for this weekend. Actually doesn't sound like the sensor at all just a little cleaning. Thanks again for the help.

 

It most often is not a problem with the sensor, just an issue with the airgap and/or dirty reluctor ring grooves. Dirty grooves really doesn't happen in the 98+ hubs though due to their sealed design.

Do let us know how you make out!

 

I will definitely keep you posted. I wont get to it till this weekend though. That o2 sensor problem seems to have cleared up too. a day in a half of straight driving no ses light yet. Cross my fingers though.