My harness has been been worked over. The diagnostic port only has one wire that goes to the computer (white w/black). The other 3 wires are power and grounds. Does that sound right? I can't believe one wire does all the talking.

 

One wire does all of the talking.

 

yep, just a single signal wire!

 

Thanks for the info! I was a little concerned that I was missing some important wires.