One problem related to electrical failure has been reported for the 2004 Chevrolet Trailblazer. The most recently reported issues are listed below.
Bought vehicle used in 2005, had 56,000 miles on it at the time. At 76,000 miles the speedometer went out completely had to be replaced. Replaced the speedometer $500. 00 cost. In 2007, the dashboard and all the gauges started going crazy, had it checked at a chevy dealer they confirmed it was an electrical problem that was not covered under my warranty and was gonna cost way to much to fix. Later in 2009 the alarm system decided it wouldn't work anymore, or it would set itself. (got locked in the car for at least 20 minutes or more, wouldn't start either to reset the process), the remote key wouldn't work as well. Had it inspected again, full diagnostic done by the chevy dealer & also by firestone, every issue that the car has is related to the electrical system failing constantly. Headlights go off and on when they feel like it, hit them they come back on sometimes, tail lights have gone out, no need to replace bulbs that is not the issue. Full diagnostic cost money, I have called the better business bureau to see what I could do to make chevy pay for this disfunctioning vehicle but, of course it is a bunch of red tape and political bull crap. I do not recommend this vehicle to anyone too much money will be lost and still no results. Currently my vehicle has over 100,000 miles on it and the gauges still go out every now and then, the headlights still go out and the alarm still sets itself when it feels like it. I pray over this vehicle everytime I get in it.