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Go Get It
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Discussion Starter #1
A common problem with the clusters in the 7th gen are the servos (aka stepper motors). The original servos are known to go bad pretty frequently. The symptoms include gauges not reading properly (such as reading 100mph when you're going 30), not seating properly (speedo sets at 30 when you turn the car off), and general erratic gauges.

If one of your gauges is acting up, you will need to replace the servo. You might as well replace all of the original servos while you have the cluster open, to avoid issues in the future. There are 3 types of clusters that came in the 7th gen, the 3 gauge in the base model, the 4 gauge in the Ls model, and the 6 gauge in the SS/LSS models. Each gauge has it's own servo, so make sure you buy enough.

In order to do this yourself, you have to be comfortable soldering on circuit boards. It's not hard to do, but it can be a little intimidating for the first timer. Make sure you have a 25w soldering iron, or you risk damaging components on the circuit board.

GM re-engineered the part with a new part number (X27.168). They can be found online (I bought off eBay) for about $5 each. DO NOT BUY THE BLACK STEPPER MOTORS as they are made in China and are inferior in every way.

This is the style of servo you want to buy. Notice the part number on the bottom portion of the servo



I used this guide for disassembling the cluster:

Impala/Monte Carlo Cluster Bulb Conversion

From here, you'll have access to the circuit board to do your soldering.

Each servo has 4 contact points with the circuit board. Desolder and remove each servo, then put the new servos in their spot, with attention to their orientation on the circuit board. Solder the new servos in.

At this point, you can begin to re-assemble the cluster. The steps are the same, just in reverse. Before putting the needles back on, plug the cluster back into the car, and start it up. Let it reach normal operating temperature, and then place the needles in their respective slots, ensuring to point the gas needle to full, the temp needle to normal operating temp (about half way) and the speedometer needle at zero. Once that's done, you can finish reassembling the cluster, and reinstall it.

It sounds like a lot of work, but it's really not. It took me about two hours start to finish, and I was also replacing all the bulbs with LEDs.
 

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Just a note, for those that might want to skip out on the 25w suggestion above. Its given to allow FAST heat transfer to a circuit board... using an iron too low will require you to apply heat too long, which usually causes the "pad" you solder to to raise and destroy it..

An iron too hot that is held on too long can also cause this, but quick heat transfer is very important and CANNOT be overlooked.

Save yourself the trouble and follow the advice above.
 

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Go Get It
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Discussion Starter #3 (Edited)
Also, as a note (after reading over BBE's disassembly instructions), I used a dinner fork to remove the gauge needles. It's a LOT easier than using a screwdriver as BBE suggests. Just slide the fork under the needle between the middle two prongs, and gently pull up.
 

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Not that you guys would know anything about this--but we had similar issues with the 05 Tahoe a suburban an 97s10--(Chevys servos suck!!!) but I took a metal eyelash curler and was able to grab the top and bottom & push slightly forward the open and it took it took it off too.. I get nervous with sharp metal objects that r n small delicate spaces when having to apply much force so--the padded edge of the curler made me feel more secure gripping it & like I had mor e control on prying befor I opened them for the final step of getting it away from board. I've used screwdrivers amongst other sharp metal objects getting various types of electronic parts of boards and sometimes a slip can cause expensive damage to delicate parts that are even more difficult to replace/solder.

But the info about the wattage of the soldering iron is spot on!
 

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Mr. Handy
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6,289 Posts
Not that you guys would know anything about this--but we had similar issues with the 05 Tahoe a suburban an 97s10--(Chevys servos suck!!!) but I took a metal eyelash curler and was able to grab the top and bottom & push slightly forward the open and it took it took it off too.. I get nervous with sharp metal objects that r n small delicate spaces when having to apply much force so--the padded edge of the curler made me feel more secure gripping it & like I had mor e control on prying befor I opened them for the final step of getting it away from board. I've used screwdrivers amongst other sharp metal objects getting various types of electronic parts of boards and sometimes a slip can cause expensive damage to delicate parts that are even more difficult to replace/solder.

But the info about the wattage of the soldering iron is spot on!
Tips and Tricks are always welcome on this forum!! :beer:

Thanks for taking the time
 

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Only question I have is will the speedometer need to be re-calibrated after replacing the stepper motors? My dad is giving me his old Impala with a bad engine, and the gauges were also wonky on the car.
 

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Go Get It
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Discussion Starter #7
Yes, the gauges need to be "reset," but not necessarily re-calibrated. The motors get the instructions for how far to turn from the databus system. You just need to make sure the needles go back on in the same place. This is where taking some pictures before hand can come in handy. Then you just observe the gauges while your driving to double-check their accuracy.

Granted, none of these gauges are what you'd consider "precision." There will always be a certain discrepancy between what the gauges read and what's actually happening with the car.
 
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