You do relize you posted an automotive question in a custom home theater forum?
But you also have someone who use to install these things 18 years ago.
Youíll need two 12vdc relays that has 5 terminals.
So 30, 85, 86, 87 and 87a.
Tape the two relays together with the screw holes along the same plane.
Create a wire harness with 4 push-on plugs all tied together. This one will be attached to 2 terminals on each relay. 85 and 87 on one, then 86 and 87 on the other. The remaining end of the harness goes to 12vdc+.
Here is a diagram of how to wire it up for the remaining wires.[Link: the12volt.com]
Now the trick is, to know what wires to test in the Van. And which switch to use. I recall having to test the wires on the passenger side while someone else used the driverís door switch. Or the other way around. Itís whatever Ford decided to do with that model.