OK, I started looking into this and noticed notes about 2001 or so with the recall to replace what looked like a 'two position' relay - however this does not exactly apply to my 2004.

Found a diagram which labels the relays.
Checked the relay #7 as per the diagram, and the one above and below both 'click' healthily on the bench, but I did not check the contacts, didn't have enough time tonight - and it is very cold and windy!
I do have an aftermarket trailer light converter; the trailer light outputs work correctly - ie the brake light connector gets power when the brake pedal is applied.

Neither the primary brake lights OR the LED top spoiler 3rd light are illuminating - my mechanic said the LED would sometimes flicker when the brake pedal was placed, I have not see this myself.

Is there anything more in the rear relay tray than just the trigger and output wires between these relays, the lights and the pedal switch?

Any suggestions would be appreciated, as it is very un-fun standing in the driveway to troubleshoot and think about this up here tonight!

Pete in Toronto