2001 Jeep Laredo No brake lights

Hi, does the high mount brake lite work? If you have good voltage and ground at the bulb socket and the bulb is good. I'm not sure where to go from there? I looked at info for grand cherokee laredo. The voltage circuit for the brake lites, the wire color is white with tan tracer. Check wire for voltage with brake switch activated. If voltage is good, check the ground circuit. At the lower rear, the tail and stop is a dual filament bulb, one filament for each circuit.