>W For example, my radio has one red wire for power
>but when I look at the hot wire from the van it is three wires leading into a
>wire harness.  What might three wires be doing here?  

Hi Rich
     With out knowing what year your van is, it's hard to identify the
wires.  Here some possibilities:
1.  Power wire for radio.
2.  Dial illumintaion wire.
3.  Ground or power return wire.
4.  Power wire for radio station memory.

Use a multimeter to determine if a wire is grounded or is a power wire.
Check with key off and on.  The radio in my van works if the key is off or
on.  I don't know if thats normal or not.  Hope this helps:-)
Colin A Moran

If you can't dazzle them with brilliance,
baffle them with bull sh*t.

 '86 Syncro GL