ABS light coming on

You need to take the vehicle to a good autoparts store and have the PCM read for fault codes. Then get back to us with codes for detailed advice. The codes will tell you/us where the exact fault lies.

Where is the noise coming from? IF the front, check to make sure the backing plate isn't rusted or bent and touching the rotor.

Abs system is different than the brake system
For the abs system you need to scan the van for codes
Possible sensor out on one of the wheels
Or if you check the ring gear for crack
Get the codes that should pin point the trouble area

Also check the float in the master cylinder ( it may be stuck at the bottom)
Make sure master cylinder full with fluid
Give it a good tap or two

Good luck

Windstar has a long history of this, and most often it's due to the EBCM or the brain of the ABS system, Ford has a recall for this, and I will cautiuon you that you should take it to Ford, go over the recall, and as the recall states, Ford will perform only what's needed to get that light out! But if you insist that the EBCM and the SCDS(speed control deactivation switch) and the new harness for the SCDS be done, you should be OK... I cant find my copy of the recall notice, but this is the recall for the SCDS and all phone numbers are on this too, give them a call and have your VIN ready!
Campaign No: 09V399000 Number of Affected Vehicles: 4500000 Beginning Date of Manufacture: 1991 JUL Ending Date of Manufacture: 2003 mar system vehicle speed control description of defect ford is recalling model years 1995-2003 windstar, 2000-2003 excursion, 1993-1997 and 1999-2003 f-super duty, 1992-2003 econoline, 1995-2002 explorer and mercury mountaineer, 1995-1997 and 2001-2003 ranger, and 1994 f53 vehicles equipped with the texas instruments speed control deactivation switch (scds). The scds may leak internally and then overheat, smoke, or burn. Consequence of defect a vehicle fire could occur. Corrective action ford will notify owners and dealers will install a fused wiring harness for the scds. Dealers will also inspect the abs control connector and repair as necessary. Repairs will be completed free of charge. The safety recall is expected to begin on or about October 26, 2009. Owners may contact ford at 1-888-222-2751. Additional information t The National Highway Traffic Safety Administration operates Monday through Friday from 8:00 AM to 4:00 PM, Eastern Time. For more information call (800) 424-9393 or (202) 366-0123. For the hearing impaired, call (800) 424-9153. Page 1 of 1 4/8/2010 ...
If you need the NHTSA website to complain:
http://www-odi.nhtsa.dot.gov/ivoq/index.cfm
If for some reason your isnt on the recall, rebuilt modules can be had for about 150.00! here's the link.
http://cgi.ebay.com/ebaymotors/Cadillac-Catera-Bosch-5-3-ABS-Module-Repair-Service_W0QQcmdZViewItemQQhashZitem35a764745aQQitemZ230441645146QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Normally it would throw out a code. Check the VSS(vehicle speed sensor) On transmission.

You'll need to visit a mechanic with a scanner that can access the ABS Computer to have the codes read. The code readers used at auto parts stores normally only access the Engine Computer. Probably the most common cause of a problem is a defective wheel speed sensor. It's important to understand though that fault codes never say to replace parts. They only indicate the circuit or system that needs further diagnosis. The part referenced in the code is only defective about 50 percent of the time.

You should also understand that when you wait a long time to have the ABS system fixed, a second, totally unrelated problem can develop and not set a code as long as the first code is in memory. That second code may not show up until after the first problem is diagnosed and fixed. That causes a lot of frustration among mechanics who have to start troubleshooting all over and tell you more parts are needed, and among owners who are sure their mechanic didn't diagnose it correctly the first time.

Nope. All that is important is all four wheels rotate at the same speed when going straight ahead. A cracked tone ring can set code and turn on the warning light but that will take from a few yards to a mile or more to occur. The crack is detected as an extra pulse per each wheel revolution and makes it look like that wheel is turning faster than the others.

Yes, pull the connector off the bottom of the master and inspect for brake fluid.

The only oil or grease that would get on a tone ring would be from the outer cv joint if the boot was ripped. Dirt isn't normally a problem because the sensor's magnetic field goes through that. Sometimes rust can build up on the tip of the sensor and that can interfere with its ability to generate a signal.

Larger tires will make the van go further with each revolution so the speedometer will read lower than your actual speed. On Chrysler products the "pinion factor" is set with a scanner to match tire size and axle gear ratio. I don't know if Fords are the same way. On older vehicles we changed the gear at the end of the speedometer cable to one with a different number of teeth.

You have to be more specific with "jittery". Do you mean how the engine is running? Shaking in the steering wheel? Where do you feel it and what do you feel?

Changing tire size affects a secondary alignment angle called "scrub radius". You won't notice that with tires that are just one size larger but when people start putting big mud tires on raised-up trucks, or when kids put low profile tires on lowered cars, scrub radius changes a lot and will adversely affect braking performance and handling. Scrub radius is not an adjustable angle. It is designed in as part of the steering and suspension geometry and helps all of the parts work together. Lawyers and insurance investigators love to find modifications that affect handling and braking. They will convince a jury that you were partly at fault for the crash when the other guy ran the red light because you were less able to avoid it, and they will be right. That's why in my classes at a community college, we never allowed anyone to modify the ride height or any part of their vehicles that affected the way it was designed.