Just bought an '05 Trailblazer after owning an '04 for the last year and a half with no issues. Got the trailblazer home, and started going over it. The temp gauge was occasionally jumping a bit, so I changed out the Engine coolant temp sensor. The jumping stopped, but the gauge was reading a bit over 210, so it seemed the fan clutch was the culprit. Changed the fan clutch, and now the real fun begins. Only has happened on startup when the gauges recalibrate every start. When it would try to recalibrate on startup, seems it was having difficulty, so the gauges would not hit 0 and then the numbers were all off on just the 4 gauges...oil,temp,alt, and gas. Took the cluster out, someone has been in it already. Looked like to me it has been worked on or changed out, I don't know which. Seems all the stepper motors were changed, I could tell from the soldering. I have ordered a reman cluster from Doorman. Question is, is this going to be a constant every couple of years that this vehicle eats intsrument clusters....or will this swap out fix this issue that GM won't admit is an issue with these Chevy's? If it is going to keep manifesting every so often....'05 trailblazer for sale with 92,000 miles LOL. A speedometer repair shop told me that the instrument calibration on startup is comming from the cluster, not the ECM or computer in the car. Whats weird is that all 4 gauges act up only on some startups, it doesnt act up every time I start it, so thats making me think the computer board is bad, not the stepper motors. Also, they all act up at the same time, not individually. What I mean by acting up is oil pressure will read 80, temp goes over 260, fuel just moves a bit off where it was, and volts is about pinned also. Ive read that when the soldering goes bad, you get no readings, not what I am experiencing with incorrect readings. Thank you for any responses in advance.