I owned a 03 and it was a gas sucking pig with a mile long list of eletrical problems. The MPG's were 12-13 in town and maybe 16 interstate even after a full tune up and new rubber, the both rear windows quit working due to the wire cable that would lift and lower the window fraying and snapping, the rear window wiper had a short in the wiring and would only turn on when the headlights were on....and stay on the whole time!
The wiring shorted out to the rear window defrost, the wiring harness shorted out to both taillights and when the brakes were on the reverse lights would glow and the turn signal would flash the other light (left insted of right..ect), then one day i went out and found the passanger side taillight smoking!!!!! the whole connector was on fire!!!! All in all it was a new problem every week my wife drove it for the 3 years we had it. I had heard that with the release of the SS most of the wiring problems were fixed but im still seeing them even today. My instructor was a Tech at a GM dealership and said they worked on more Trailblazers than coolant leaks on GM 3.8 engines.
thanks for the heads up. Going to do a little more research right now.