I have been looking all over for someone who has detailed instructions (with pictures) of where to find the reverse wire in the front of the vehicle not the rear and the VSS (speed sensor). I have an aftermarket head unit and am looking for both wires to make everything work properly. If anyone can help please send info. This is for a 2007 hummer h3 base model

 

All wires are color coded to specific circuits. Some are solid, some have a tracer (a line in the wire with a different color)
You can find all the wiring for your rig here:

http://schwarttzy.com/wp-content/upl...iring-2007.pdf