On my previous (Ford) truck, I had a dealer install a
cheap Reese break controller, so afterwards when I
bought a my Prodigy, I just disconnected the
black/white/red/blue wires from the Reese, and connected
them to the Prodigy, and it worked great...

Now I have a new 2004 GMC Sierra 2500HD, and after 5
minutes on my back, I couldn't identify the 4 wires
under the dash board. I am really in a hurry to get
this installed... anyone out there with a Sierra or
Silverado that can tell me where the wires are???
Pictures??? Note: I'm totally illiterate in regard
to what's located under the dash-- so a non-technical
description would be appreciated!

Thanks!
Paul.

No plug and play harness ?? The 2001 2002 harness are different then the 2003 .... I have to imagine the 2004 is same as 2003 ...
What I've heard :
On a 03 where your left foot would hit the floorboard is a black box with one hand screw in the center.....On the back of the cover is the wiring diagram....The plug in is the one in the middle top of the junction box.....

Harness (http://www.brakecontroller.com/)
Plugs into the Prodigy controller and the fuse block and no wire splicing needed.....

Mac http://www.dieselplace.com/forum/smileys/Confused.gif

With some help, I figured it out...
Check out the details Here (http://www.rv.net/forums/index.cfm/fuseaction/thread/tid/13060214/gotomsg/13060751/p/1.cfm#13060751)

Paul.