ABS Light comes on @ 75mph

[CBoug76]

Ok,
When I get my truck up to 75mph, the ABS light comes on, and stays on...
Untill I cycle the Key. As long as I stay under 75mph the light stays off....

anybody have any idea what this problem is? and How I can fix it?

 

[Runnin'OnEmpty]

Cboug, of course the first thing is to check for codes, but short of that I'd suspect the VSS (speed sensor) located on the rear differential. Since the CEL/MIL only comes on at higher speeds, maybe it's simply dirty. I've heard of people cleaning these, but haven't any first hand experience on doing it. The VSS is magnetized and tends to pick up tiny metal filings from the diff mechanicals.

There are ABS sensors in the front end also. Checking the codes might be helpful in narrowing the problem down a bit.....if it's a P0500 through 504 code then I'd suspect the VSS.
ROE

 

[dogfriend]

The VSS for 97 is located on the trans extention housing (2wd) or transfer case (4wd). I believe that 98 was when they relocated it to the rear axle.

You need to find out what code(s) are being set. I wonder if mine does this - I rarely drive faster than 70 mph.