2006 gmc sierra wiring verification?

On some of the GM trucks, both full size and smaller, you do need to hook up the Brown 2nd accessory wire. It depends on certain options in the truck. It doesn't hurt to do it and will always prevent a problem if you are unsure. It is fine to tie into the wait to start wire at the cluster on these trucks. You need to make sure that it is the correct blue wire in cavity A2. It is a negative trigger circuit. In 2002 adding a relay to invert it to a positive pulse caused problems on some trucks. You had to use a transistor to reduce the load it presented to the circuit. After that, adding a relay wasn't a problem. The other side of the relay coil had to be an ignition source though. As with anyhthing else, hooking into this wire probably got a bad rep. because some installs weren't done correctly.sparky