Three ways to get the wiring info.:
(1) Some dealers will let you look at their FSM's in their facility - used to be that way - I don't know if they still do that.
(2) Buy the FSM (probably more than the approx. $100 they used to be).
(3) If it's worth $25 to you (for a one year subscription), you could get an on-line subscription to alldata.com. Not sure about your van, but for the vehicles I have subscriptions for, they have every single schematic that's in the FSM, and they are all right out of the FSM - none of the aftermarket manual "typical" schematics that may or may not be accurate for your vehicle. With that subscription you would also have access to the complete TSB's applicable to the vehicle - that alone might be worth the cost of the subscription.
(I have no connections with alldata other than being a customer - and to prove it, I'll say that the rest of their vehicle-specific information, though right out of the FSM, is spotty, incomplete, and poorly organized/hard to search. Schematics and TSB's are 100%, and may be worth the cost by itself. Also, they give multiple year/multiple vehicle discounts.)
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')