I have a taurus wagon and the top brake light on the gate works but the two bottom lights do not. Bulbs are good, reverse lights work, and signal lights work. Any suggestions on what to check or what the problem is?

How do you know the bulbs are good? Are they the correct bulbs? Are you getting power to the bulb sockets? Is the gound going to the bulb sockets good? Use a jumper wire to by pass the ground. Do the sockets look coroded? Do you have a wiring diagram? Wiring diagram is helpful in finding a common point where a wire failure may occur.