My truck is a 1999 V8 5.4L F-150 FX4 with the electric shift 4WD. I have two problems that I think that they could be related. First off my ABS light turns on solid when i shift to drive and accelerate to about 2 mph any time i drive. My other problem is my 4WD. When I turn my **** to 4WD H or L (of course going to low through neutral) the trucks front wheels will not pull at all. All the 4WD lights in my dash seem to work properly. I have been doing some reading and was wondering if both of these problems could be the result of a faulty VSS sensor. If anyone has any tests I could perform or any advice on how to fix these problems or if someone could tell me if these problems are even related, it would be greatly appreciated.

 

I got it fixed my abs was a speed sensor on the top of the rear differential. My 4WD problem was a faulty vacuum actuator motor.

 

Thanks for posting the solution. i always appreciate shared knowledge. Welcome to the forum.

 

I read ur first message and knew the 4x4 problem would be vacume realted. So dissapointed I couldn't be the one to help u