Trailblazer Speedometer

Between 2003 and 2006 GM produced thousands upon thousands of Trailblazers with speedometers that had defective parts inside.  Little did they know later on some unfortunate owners would be stuck with bad speedometer gauges.  Flash forward a few years and the problem has gotten pretty huge but GM has taken a pretty hard line on the subject.  Although there was a factory recall of sorts it was fairly limited in what models it covered, see the links below for more on that.  They usual cost of repair, if you aren't covered under the recall, is typically $400-$600 at the local dealership, local independent mechanics usually aren't much, if any better.  This leaves the disgruntled Chevy Trailblazer owner with just a couple options: Replace the speedometer with a used one from a junk yard vehicle or repair their original speedometer.  Let's take a look at both options for a few minutes. 

Should I Buy Used? 

First of all you can certainly save some cash by purchasing a used speedometer, that's for sure.  Used speedometers for Trailblazers can sometimes be bought for $50-$150.  But, you may agree that some of the downsides are worth taking a look at, read on. 

The first problem is, you're replacing a part with a recognized problem with another part with the same problem - failing parts inside the unit.  When you do that you're taking one step forward and two steps back.  It's only a matter of time until the "new" used part goes out just like the original one. 

Secondly, with a junk yard speedometer you need to be aware that the vehicle mileage on the odometer stays with the instrument cluster - not with the vehicle's main computer.  So, if your Trailblazer odometer shows 90,000 miles and the speedometer you pulled out of a junk yard shows 160,000 then your truck will look like it has 160,000 miles and your truck will be worth a lot less when you go to sell it!  And, on the other side of the coin if you put in a speedometer with 20,000 miles you'll be committing odometer fraud and they'll catch it during the title work!  Those problems can be solved by having the odometer re-programmed to your correct mileage but by the time you've paid a mechanic to do that plus the cost of the used part the total price has gotten pretty ridiculous. 

Can I Repair My Speedometer Assembly? 

Yes, and for many truck owners this is an attractive option that works well for the do-it-yourself folks out there who like to save some cash and prefer to do their own repairs and maintenance.  Probably the first advantage here is cost.  For a very reasonable amount you can get all the parts needed to do the job, instructions and maybe even a little left over for a couple tools - not a bad deal at all. 

The second big advantage here is time.  If you go this route you can order the instructions and parts ahead of time then find a time that fits into your schedule to do the repair - which only takes about an hour or two if you go slow and steady.  Check out the instructions at this link if you are interested in doing the repair yourself:http://www.instructables.com/id/DIY-Finally-How-To-Repair-a-GM-Instrument-Cluster-/

So, in conclusion I hope this short intro has helped to shed some light on the speedometer issue with Trailblazers and has given you some ideas on how to move forward if you are suffering from the problem.  Be sure to check the links below for more discussion of the specific problems the speedometer and other gauges often have.