One problem related to dash wiring has been reported for the 2005 Chevrolet Trailblazer. The most recently reported issues are listed below.
The headlights/dash lights started flickering. The battery voltage meter was jumping back and forth. The headlights would go out and then come back on. I was not able to duplicate this problem. There were no codes stored in the computer from the incident. It has happened since 11/23/05 at least twice.