04 chevy blazer 5701 xk09

I'm a little confused.

Just to clairify, you have a 2004 Chevrolet Blazer.  Not a TrailBlazer.

For 2004 Chevrolet Blazer, DEI lists the  XK09 as a Passlock II bypass with the PLXR V3.03 firmware.  (The XK09 module can be loaded with 10 different firmwares for various vehicle applications.)  In the XK09 PLXR Install Guide, your Blazer is listed as a Type F install.

At the ignition switch the Passlock wires should be Yellow (r code) and ORANGE / Black (ref). 

I am not sure what firmware comes preloaded on the XK09.  Most XK modules have a red label that has all the firmwares listed and a "x" in the box next to the one that is loaded.  If your module does not have the correct firmware, you will need to get the XKLoader cable ( about $50 ) to connect the XK09 to your PC to flash the correct PLXR firmware via the internet.

The XK09 with the PLXR firmware will only bypass the PassLock II engine immobilizer on your Blazer.  The install guide is available at the DEI web site:  http://www.xpresskit.com/VehicleCompatibility.aspx?v=1360&ps=1     Look up the XK09 and download the PLXR install guide.

The best way to check wires is with a Digita Multi Meter (DMM) ( about $30).  Trained professional installers use them, especially around sensitive computer modules and the air bag circuitry.  Blowing a cars computer or air bag is very expensive.  In the steering column the air bag control wires are usually in a yellow loom or marked with yellow to alert repair techs, but not always. 

As an example, to locate the Accessory wire at the ignition switch, you would first obtain a wire listing.  There are several sources like Bulldog Security:  http://www.bulldogsecurity.com/bdnew/vehiclewiringdiagrams.asp    This site has a wire listing for your Blazer, too:  https://www.the12volt.com/installbay/forum_posts.asp~TID~50373    Hopefully they are the same, but not always.  That is why its very important to check, verify and double check every wire with a DMM.   Next you would look for a orange wire at the ignition switch.  As a trained professional, you would know that it should test as +12v when the ignition switch is in the ON or ACC position and be 0v in the START and OFF positions.  Set the DMM to DC voltage at the 20v setting, put the Black lead to chasis ground and the red lead on the suspect Orange wire. Here is a link to a install guide for a R/S made by DEI : http://www.designtech-intl.com/pdf/manuals/24923.pdf  It will give you a basic understanding of wire locating and testing.  The door lock section to very good, also. 

As far as the Passlock wires, they are smaller gauge and usually grouped together.  Look for the Yellow, ORANGE / Black and RED / White wires grouped together.  Most professional installers can pick them out fairly quickly ( past experience ) and know how to test them with a DMM if they are not sure.

While I won't tell you to have the R/S professionally installed. I think you can see that it takes some expensive tools and equipment to install auto electronics and without the proper training you can cause a lot to damage to your vehicle.  Additionally, all of your wiring connecions should be soldered and wrapped with quality electric tape or insulated with heat shrink tubing.  ( A poor connection at the passlock wires will cause the car not to start, an un-insulated +12v constant wire shorting out against the dash frame will be worse.)  A good supply or tie wraps,  diodes, etc are usually needed as part of the install.

The Viper unit you have is fairly sophisticated.  It has a lot of programming options that need to be configured.  The install guide is available on this site as a download.

The usual way to check the passlock wires via voltage is by placing the DMM black lead on the refference wire, ORANGE / Black, and the DMM red lead on the Passlock r code wire,  yellow.  Of course, to do this you first have to locate both wires.  I believe with the key off you should get around 4.99 volts and at the start position it should be less.  ( I use a different bypass module, iDatalink ADS TB, that accomplishes the bypass thru Data and does not attach to the PassLock II wires.)

If you look closely at the ignition cylinder you should see the wires coming right off the ignition cylinder.  Unfortunately, I can't find a picture for you.