99 Sub- 6 wires going to fuel pump!

My wife's 99 burb is dead. I know the engine is not getting fuel and I can't hear the fuel pump when I turn the key to the on position. In trying to avoid the trial and error method with the relay I wanted to see if the pump was getting juice when I turned the key to the ON position. I couldn't find the plug between the fuel pump and the main wiring line so I thought I could maybe open the wiring jacket and carefully poke a line to see if it's hot. What's up with the 6 wires! (2 black, 2 gray, purple, green and my memory is failing me). Will I have to drop the tank anyway?

There are 6 wires because the sending unit (for the gauge) is also in the tank.

I am pretty sure there is a test port on the firewall to give power to the pump for testing. I don't know where it is on the 99 but I am pretty sure it should have one.

//2000CAYukon

My experiance: I had to replace my fuel pump 4 years ago at 65,000 miles. I recently replaced the pump twice because it wasn't working, but I realized that the pump was not the problem. I checked all the wire/cable connections and found that one of the cables that plugs into the computer was partially unplugged on one side. This was occuring because the (Texas) heat under the hood caused the cables and wires to slightly sag, pulling the plug partially out.