Sounds like an issue with the front sensors/wiring harness. Anyone been messing with front brakes, bearings or axle lately? First thing to try is simple. *Gently* remove the front sensors, clean the grundge (metal filings, grease) off the sensor. Clean it well. Gently means to avoid bending or pulling on the wiring or connectors. Be sure to clean well around the sensor before pulling it to avoid contaminating the birf grease as this ledge collects an incredible amount of oily grime and grit. Whole thing shouldn't take an hour.
Also, what's the status of your tires? Are they all the same age or is it unknown?
I had this same problem, I would go to stop on dry pavment and the ABS would kick in and the ABS light would flicker (I think, it has been a while). First thing I did was the cleaning that Doug spelled out for you. I did this and it stopped engaging, but it also stopped working. I have now driven with my ABS light on for 8-9 months. I don't have the cash to drop for 2 new front speed sensors. They only come in pairs also. I have had no issues at all with not having the ABS and have tried to lock the tires up in a empty parking lot. I had to try 3 times to get them to lock. Even HEAVY emergency braking would take alot of pressure for them to lock.
That result is exactly what I'm trying to avoid for him - the sensors and harness are expensive parts that can be damaged with rough handling. I'm not saying you did that, but it is one outcome of pulling the sensor out without disconnecting the nearby wire mount, or twisting the sensor around to look at it because you're doing all this from under the truck vs taking the front tires off for way superior access, etc. Do this one right and odds are good you'll take care of an annoyance. Do it wrong and you'll find out how expensive any ABS related component is. Thanks for the further input, TX.
Mine only kicked in a couple times and then it threw a code and stopped working all together. Cleaning mine didn't help. I reread my post and it did sound like I was saying taking them out ruined mine. It didn't I am sure they were toast before I pulled and cleaned them. But it was worth a try. But Doug is right, these are VERY fragile. I can't imagine trying to get it out without jacking the front end up and pulling the tire. This is for sure the RIGHT way to do it to avoid any accidents with you sensor or harness.
Mine also had some metal shavings on the magnets- this is normal and unless there was A LOT - not attributed to your Newfields...no worries.
Kurt you may want to reset the ECU after you button everything up, even though it hasn't thrown a code might help.