Maybe too late, but it's easy to 'partially' open one of the lighting circuit connectors causing your observed fault.. having completed over 100 hi end stereo installs in Commodores over the years, this happens. You should be seeing "Check tailight globe" faults on the dash in VE and VF models.. It's possible to open up the 'Body Computer light connectors (close to steering wheel), and apply 12v power to check wiring and globes independently.. but NEVER place power on the globes with the Body Computer connected.. You need the wiring diagram to do this..
-->>sorry, I didn't see your resolution.. in future just be careful probing, and disconnect the battery when doing wiring updates, crucial in these days with explosive air bags..