VCCA Home Forums TECHNICAL - GENERAL Trucks and Vans Chevy truck 04 05 instrument cluster failures

mack: how many syepper motors do you need?mike

I had my '04 speedometer stepper motor changed and recalibrated by a shop in Houston. Cost me $300 versus the $600-$700 that the dealer wanted. Got my $300 back when I bought my '08. Yes, it was actually an extra $300. My father was a car dealer so I know the tricks.

I think that there are six stepper motors in the cluster.
I did a "stepper motor" search on Google and came up with multitude of stepper motors for sale.

I have two of the stepper motors that are bad right now, the speedometer and the volt meter don't zero. I am using my GPS for speed and a Vector voltmeter plugged into the cigarette lighter socket for volts. The speedometer zeros at 45 MPH (110 Mph is a true 70 MPH) and the voltmeter pointer is reading at about 5:00, but it appears to be moving in the correct direction.

I found a guy in Oklahoma that will do the complete cluster for $99 and I probably will go that way.
He will replace the steppers with the X-27-168 motors, re-calibrate and update to the latest updates. There is a software program that provides the latest updates.

Isn't the 27-168 the latest model?

By the way, Stepper motors are fairly cheap, However, every site on eBay that advertises stepper motors for sale expressly state that once they are sent that they won't be warrantied due to the risk of damage by amateur installation. The shop that I intend to send my instrument cluster for rebuild, does warranty their work and parts.
I feel quite competent to do the installation and have the tools to install them and can download the GM software to update the cluster. I want the satisfaction of having a warranty and think that the extra time and money is worth the sending the cluster off.
The Tahoe is drivable without the cluster. I can use the GPS for speed and the portable voltmeter. Careful pre=trip inspections should be enough for tach, oil pressure, and temp, and logging trips with the GPS should take care of no odometer or fuel gauge.

Maybe we will just stay within the county.

Mr Mack,
I don't currently own one of the trucks you are discussing but am very curious as to what a 'stepper motor' is and why GM's electrical engineers would put 6 of these critters in an insrument cluster. Somehow have the impression that it relates to digitizing and complicating what was once a simple, reliable affair.I guess the KISS principle doesn't apply to current vehicle engineering.Reminded again why we keep our old dinosaurs running. Good luck with your repairs!
DFC

I put a set of stepper motor gets in our daughters Trailblazer last fall, paid about 28.00 for the set shipped. Was very easy and they came with instructions.

DFC,
Stepper motors are one way to convert digital data or input to an analog appearing device. In other words they make the gauges read just like the old analog type we are used to.

this is not so anymore (have you priced a new mechanical analog set of factory gauges or speedometer? lately? and these stepper motors cost less than about $70 for 25 motors each on eBay, just guess how little GM pays for 100 million of them? Bad thing is if you buy 100 million bad ones! I reckon you roll the dice and hope that they last for 72001 miles and the customer will bear the repair. There is no way GM can justify charging a Chevrolet customer $400 to $600 for a new cluster...with the same old sorry stepper motors that go bad!

If your instrument cluster starts acting weird, one or more gauges..Go to your dealer and show them how cheaply that you can get a cluster rebuilt with good stuff and warranted for the life of the vehicle. Then after you explain how badly you are getting ripped off by G.M. go up to the sales floor and throw yourself a hissy fit!




Here is the X-27-168 stepper motor used as an updated motor on each of the gauges, tach and speedo on a GM truck cluster (6) in each cluster. The ones used in the original clusters that failed were an older generation.

However, don't get down just on GM for using the stepper motors, most everyone else also uses one form or other of stepper motors in digital instruments with pointers.


GMC GM Cadillac Buick Chevrolet Chevy Pontiac Cluster x27-168 Stepper Motors (this side it the side that the pointer is attached to) This pic is bigger than lifesize


complicating what was once a simple, reliable affair.

Gee Mr Mack, I was only funnin ya about the digital insruments and stepper motors. I pretty well understand the how and why but given the solid state nature of the technology one would think the reliability should exceed that of the old analog mechanical units. A 'batch of bad ones' explanation just tells me how inadequate the industry QC is. Interestingly, with about a dozen Chevy/GMC vintage vehicles all the gauges work and except for speedo cables have never needed repair or replacement. Now they are probably not as accurate as the digitals but darn reliable. The biggest headache with digital electronics is they either work or not! That can leave you stranded in the boonies calling AAA cause roadside fixit is rarely. I remember 3 days in a motel room waiting for a tranny control electronics to be trouble shot and fixed. And then there are retrofits-how many vintage cars with Petronix modules have owners carrying points and capacitors? Progress is good but it's fun to grumble about the downsides.
Again, good luck with them motors, Mr Mack.
DFC

Well, the failures on the 04 and 05 model gauges are the exception to the usual rule. bot look at it this way. My first failure was at 124,000 miles. after having most of the front end replaced because of hitting a big buck deer. I didn't even know what a gauge stepper motor was until I was told that the entire cluster would have to be replaced for $400 plus. I consider the education worth something. The reliability factor for all the stepper motor clusters made by GM must be somewhere around 1 in 50,000,000 @ 72,000 miles. Our vintage analog gauges won't do near that figure.

I'll buy your explanation, Mr Mack, but have to say we usually shoot our buck deer in Arkansas---- it's easier on the truck (grin). May the skys open up to give us much needed rain. Have a goodun.
DFC

Thanks Dan, We are forecast to get some thundershowers, God has been good to us. We had 2 inches of rain last week, this should make the deer critters happy, they think that they are in deer heaven this spring as opposed to that awful drought last year, with all the pecan orchards around the area. Is it dry up there in Arkansas?

One thing I would be concerned about in doing a DIY cluster repair (changing the steppers), is if the controller for the cluster needed a software upgrade or calibration. This is done at the speedometer shop I have contacted, he is just a few miles from Fort Smith. I know that a quality upgrade to the cluster involves using the GM tis2web software.
I suppose that if the controller is functioning correctly it does not need "flashing"? Flashing is what I understand the dealer calls reprograming the controller. That is all that the local GM dealer can do besides changing out the complete cluster at $400+.

MrMack,

At $400.00 + Im willing to bet that the cluster you would receive would be a reconditioned unit from some other poor smuck's vehicle that experienced a problem simular to your current one. I'm guessing a new cluster is somewhere north of $1000.00

I don't doubt that either!

I noticed that by your profile that you are an Auto/Tech shop owner, that should have helped you install the stepper motors, right? Did you have to re-calibrate or Flash the cluster?

Hello dens41
Did you hace to recalibrate the Trailblazers cluster?

No I just replaced the stepper motors, all 6, even though only the speedo was the only one giving problems. I think the only time you need to do a reflash is to put the correct mileage in a replacement cluster.

Ok, I still plan to pull the cluster and send it off to Brian's Speedometer repair Center in Muldrow, Oklahoma for a complete rebuild. Mainly because of the full warrrenty on his parts and labor. We had a trip planned for this weekend so I didn't send it yet, it will go out this next week, I'll post how the transaction came out once it is back in the Tahoe.

Here is a link to his Brian's Speedometer Repair web store:

dens41, one more question, please, How did you know where to place the pointers on the new stepper motors, or does it matter?

Do they self correct when the power is restored? UH OH! that is two questions!

Ok, does anyone know the answer to these 2 questions???????????

When you put the needles back on you line them up with the mark on the masking tape that you made before you removed them. The stepper motors have a stop as you install the needle you turn them counterclockwise as you are pushing them on. The stepper motors that I bought came with instructions.

Ok..so the directions that came with the stepper motors show this? Thanks!

Yes the directions were very good. I should still have contact info for the place I got them, and can look if you want.

I pulled the Tahoe's Inst. cluster A week ago today (7/7/12)a 10 minute job, and shipped it out UPS Monday at 3:00PM It arrived back by UPS Friday morning. I installed it ( I took a bit more time and was careful, it took 15 minutes and required a 7mm 1/4 inch drive socket) and was back on the road by Friday noon. The cluster arrived in the same box and with the same packing that I sent if off with. The cluster looks great! works great! I consider the transaction with Brian's Speedometer shop in Muldrow Ok excellent. For $99 and one-way UPS shipping to Muldrow I am satisfied... beats paying $400 to $600 for a new one at the GM dealership, with a new cluster they must keep your car (about four days) while the work is being done to be sure the correct mileage is cranked into the odometer. Plus it has a lifetime warrenty for Brian's work. Since he replaced all the stepper motors, bulbs and LEDS and calibrated the cluster, so far I am satisfied.