It was suggested I cross-post this here from the Econoline forum, I hope thats not against the rules in any way, and if it is I won't do it again...

I've got a '97 E250 with what appears to be the factory tow package- it has all the fuses and relays under the hood, and I've got a plug by the e-brake that connects to my brake controller (which gets power at this point)

I've been given a part number from Ford (xc2z13a576ba) for the factory harness. They say it should plug into a existing pair of connectors under the body someplace.

From what I understand, someplace on the van there is a connector or pair of connectors that has the 7 signals for my trailer plug. But where is it? I put the van on a lift today, and I didn't see anything jump out at me from below.

It is a extended cargo van if that makes a difference. I did a search, and all I got was results looking for the other end of the plug, the one the brake controller plugs into...

 

dont know if this will help but I had an 89 F250 with the tow package and got the wire bundle also. Found the plug back near the hitch (not installed in them days). I saw a picture of one on a new vehicle and they showed the plug for aftermarket on the driver frame just back by transmission.

Go to etrailer.com and look at the aftermarket wiring setups they have pictures etc.