Ok folks for us 97/98 owners its not as easy but it is possible, I just finished doing this to my 98 venture and heres the answer... There is no DIC connector in our vans, heres how I did it.
I purchased a 99 Silohuette OH console, and lucky for me they just clipped the wiring harness unstead of leaving out the connectors.
in the 97/98 venture the DIC wires end on the pillar between the right sliding door and the front right door. If you pull the seatbelt off and the covers off you will see a black junction box right below the seat belt pully. If you look one side of this box has all the DIC wires you need, This is where they end. GM in there ifinite wisdom decided not to put an extension.
So what I did was get some extra wire and directly splice into these wires, ran the new wire up to the overhead console and connected the connector they sent with the console. Plugged it in and voila it worked. Fortunatly the temp sensor connector was indeed where it neded to be. And I checked and the rear power window conectors are there, They also get power when I push the button. So rear power windows here i come.
Hope this helps out.
PS. The yellow wire that has voltage while the key is on (But not started.)is the Fused Accessory Feed, The other one doesnt seem to have any current on it while the key is on.