Trying to find missing switch for outdoor light
Make sure the light bulb is good.  

Measure voltage across those 2 wires.  Does it read full line voltage? 

Remove all the light bulbs. Does the voltage change?  (It might be "phantom voltage").  

If the voltage is there with the bulb in, and gone/diminished to phantom when the bulb is out, then it probably is a switch to the bulb.   The next test is to connect those 2 wires to a receptacle, and plug a lamp into the receptacle. (really works best if the lamp has a switch).  Now put same-size incandescent light bulbs in both lamps.  

Does turning the temporary lamp on cause the other one to light up?  If yes, are they both about half brightness?  If so, that settles it; that's a switch to that light.