Just curious whether you ever got this resolved Thmstec. If not, something else you could try would be to disconnect each of the three lights one at a time to see if there might be a problem with one of them that is affecting all three, like maybe an individual grounding problem, or shorted portion of a circuit.
Building on what Greasmonkey was saying also, if you have a voltmeter, checking between a chassis ground and all of the Red wires in the connectors that go to the brake switch, both noise suppression filters, and all three of the light assemblies in question will tell you if you are getting power at all the places it's supposed to be.
And you never did say whether you had been doing any other work to the VX lately that might have in some way contributed to the brake lights stopping working; ie: a connector that might not have been snapped back together as well as it could have even though it felt like it did at the time, something simply not getting plugged back in at all, etc.