My 05' H2 SUT had the infamous speedometerjumping needle and reading wrong speed. It alsoseemed the speedolight was dim.Stealership wanted $640 and the SUT for two days to replace it (not repair it). The problem is the "stepper motors" in the cluster. Theproblem of course, is a service bulletin but not a recall item. GM trucks, Tahoes, Hummers and others experience this problem.

I found Carl Cowles, a.k.a. Digital Dash Solutions on Ebay Motors. Their phone number has changed and is860-583-0629 and they are located at 140 Frederick St., Bristol, CT. 06010. For $109 + shipping, they will fix,testand warranty the specific problem with our instrument clusters. For $173.50 with return shipping included, they willreplace all the stepper motors andlight bulbs, update, test and warranty our instrument clusters.They will also sell you a rebuilt instrument cluster for $250. They also have custom colored guage needles.

Its very easy to remove our instrument clusters and you do not remove the whole dash to do so. You only remove the part of the dash surrounding the cluster.To do so,unscrew left vent cover bolt, unscrew lower left and right bolt in dash cover surrounding cluster, and I also unscrewed top left bolt in center vent cover. Thenyou slowly pull cluster dash cover out. Then youunscrew four (4) screws holding cluster. Thenyou carefully unplug one connection behind cluster.

I sent mine off for a full rebuild and just reinstalled it. It works great!

 

Great information! Thanks

 

I bought 5 Chevy Diesel trucks on the same day and less than a year later 3 of the trucks speedometer needles are broken and reading the wrong speed, I think its a screw up on GM`s part

 

YEH YOUR DEALER IS CARZY. I KNOW WHAT WE PAY AND ITS NOT EVEN CLOSE TO THAT

 

I had my instrument cluster repaired by myairbags. Been working ever since

 

how far off was your speedo? I just bought a SUT two days ago and found out its about 2-3mph off

 

Its a common problem with all GM trucks and Hummer's. We have replaced a few over the years, at least its an easy swap with only basic hand tools.

 

I only had the problem occasionally then things would start working again occurred for a couple of years, along with other little nuisance cabin computer controlled electrical problems. Speedometer would be 10mph lower then stop working all together, but only when the engine was hot and running fast. Everything would reset within 1-4 new start ups. Was also getting battery drains and no starts (with ignition switch locking) ever so often.

Fixed wires at shifter, put whole in steer column cover - fixed everything, but the speedometer which didn't really bother me that much as I already know that I drive too fast.

Finally got an indicator light showing (70mph) that AC was not charging, and the speedometer would act up - car felt slugish. When I would slow down 20mph the indicator would go off and car would run normal.

Bottom line, the Alternator would fail, but only at high RPM, which would screw up the e-system. Alternator fixed - no more speedometer problems and no more other little computer electrical issues I was having.

Make sure to check alternator at different rpms.