ford windstar bypass info needed

The 556SW will work for your van.  There are a couple of things to point out.

You must have two working, non-clone, keys to program the 556SW to the van.

Placement of the antenna ring on the key cylinder is important.

Very cold weather can affect the performance of the 556SW.

Very simple connections to the remote start unit.  Just follow the guide.

The original transponder keys for your van were unique keys ( transponder chips ), each programmed to the van.  A replacement key can be another unique key or it can be a clone ( duplicate chip ) of one of the already programmed keys.

Starting during the 2001 model year, the Windstar transponder immobilizer system was changed to the PATS3 type.  The PATS3 immobilizer system requires two unique keys to add another key to the vans system ( there is also a maximum number of transponders allowed on the system ).  The 556SW, as far as the van is concerned, is just another transponder key and is programmed the same way.

The antenna ring is the 556SW's way of transmitting its' transponder chip info to the vans immobilizer system.  The remote start turns on the 556SW and the 556SW, thru its' antenna, brodcasts its' chip info just like a working key placed in the ignition cylinder.

For you, the DIYer, installing a remote start in a Ford with the PATS3 immobilizer system, you will need 2 working, non-clone, keys to program any bypass module.  Getting another transponder key made and programmed to the vehicle usually requires a trip to the Ford dealer.  Some hi-tech locksmiths have the ability, too.  Personally, I would want to have 2 keys to any car I owned for obvious reasons.  

The transponder chip in the 556SW will act as a "key" ( be accepted by the PATS3 immobilizer system ) once it is programmed to the car.  If the van came with 2 keys, one was lost, then you got a new key from the Ford dealer and then you programmed the 556SW to the van, that would be 4 transponders valid on the system.

There are two parts to the key.  The blade with the correct cut for your lock cylinder and the transponder chip.  If you got a plain blank key ( no chip ) and had it cut, it will open the doors and turn in the ignition cylinder but the engine will not start / run.

Short of diasbling  the PATS3 system ( which is a taboo subject on this forum ) or you having the install done by an authorized iDatalink dealer, you need two keys.

The 556SW install guide I just downloaded from the DEI site really doesn't show any illustrations of the antenna placement on the ignition cylinder.  If you download the 556UW guide, it has some illustrations of the antenna placement.  http://www.xpresskit.com/product.aspx?productid=44