The Cabela's light contains a secret shared by no other light I've ever seen. Connect an Ohmmeter between the positive and negative poles of the tailcap and the meter will show nothing. Now click the button on the cap and read it again. Still nothing. This would lead one to think that the tailcap is bad, but it's not...at least not yet. The reason you don't get a reading is because there's a diode inside the tailcap. It acts as a reverse polarity protection for an LED module, should you choose to use one.
In order to see if the tail switch is good, remove the head of the light and run a meter between the positive terminal of the front battery and the body of the light. If there's no reading, click the tailcap and try again. If still no reading, the tailcap is bad (meaning that the diode has gone bad, most likely from shorting out against the ground part of the switch. If this occurs, reach inside the tailcap with some long nose pliers and unscrew the interior part of the cap (see picture below). Then gently pry the metal edge from around the green circuit board until you can remove the guts of the switch. Cut the diode out of the circuit and run a jumper between the board and the switch, being sure to insulate the jumper from grounding. Then replace the green circuit board and tap the metal edges back to hold it in place as before.