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Discussion Starter · #1 ·
Wondering if anyone has ever seen this issue. Google search didnt turn up any results that I could find...

Truck is a 2015 Sierra 2500, when I start it sometimes the tach and speedo will cycle normal and funtion as they should. Other times, the tach will cycle and almost twitch then it wont reset to the actual RPM, so it will be a few 1000 off but work properly. Other times the needle will just freeze and not work at all. I can rely on my Cts2 for now, but its rather annoying to show 5000 RPM at idle...
 

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The little stepping motor that is the tach is probably failing-- you can buy them on Amazon or send the unit to one of several people that repair them. Simple job to do if you can solder well.
 

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Discussion Starter · #3 ·
The little stepping motor that is the tach is probably failing-- you can buy them on Amazon or send the unit to one of several people that repair them. Simple job to do if you can solder well.
So the motor is behind the gauge cluster? If I pull it out ill likely see it?
 

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Discussion Starter · #4 ·
Also, I cant find any stepper motors for anything newer than '07. Are they pretty much universal?
 

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You might have to send out to a repair shop. I couldn't find any reference to any clusters beyond a 2013. I wonder if GM changed the circuit panels to something other than steppers.
 

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Wondering if anyone has ever seen this issue. Google search didnt turn up any results that I could find...

Truck is a 2015 Sierra 2500, when I start it sometimes the tach and speedo will cycle normal and funtion as they should. Other times, the tach will cycle and almost twitch then it wont reset to the actual RPM, so it will be a few 1000 off but work properly. Other times the needle will just freeze and not work at all. I can rely on my Cts2 for now, but its rather annoying to show 5000 RPM at idle...
sounds to me like a bad stepper motor, but i would not expect to see one so new fail.
 

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Remove the battery cables. Have a beer, or two. Hook up the cables before you start tearing the dash apart. Check your battery volts. Hey, sometimes it works.
 

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Remove the battery cables. Have a beer, or two. Hook up the cables before you start tearing the dash apart. Check your battery volts. Hey, sometimes it works.

^^^ your not wrong, if you want to do that without the beer break though, disconnect all 4 battery cables, and tap 1 + and 1 - together and it will drain all the capacitors in the system accomplishing the same thing in seconds. That said, if you want an excuse for a beer break, dont let me stop you :grin2:


This reset trick has saved my butt more than once.
 

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Discussion Starter · #9 ·
^^^ your not wrong, if you want to do that without the beer break though, disconnect all 4 battery cables, and tap 1 + and 1 - together and it will drain all the capacitors in the system accomplishing the same thing in seconds. That said, if you want an excuse for a beer break, dont let me stop you :grin2:


This reset trick has saved my butt more than once.
Sounds sketchy! lol
 

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Sounds sketchy! lol
how so? there are many capacitors in the various computers that store a charge and they need to be drained to reset things. If you let it sit there for a while disconnected, eventually they will drain due to parasitic loads and minor resistance in the circuitry, or if you touch the cables together (with no battery hooked up) the small amount of energy in the capacitors is released instantly. If you were really worried about it you could put a resistor between the + and - cables to limit current, but ive never had an issue with it on many different types of vehicles.
 

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My neighbors kid just did it on a Bass Tracker?Mercury engine that was giving him a high temperature alarm. And it worked.
 

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Discussion Starter · #12 ·
how so? there are many capacitors in the various computers that store a charge and they need to be drained to reset things. If you let it sit there for a while disconnected, eventually they will drain due to parasitic loads and minor resistance in the circuitry, or if you touch the cables together (with no battery hooked up) the small amount of energy in the capacitors is released instantly. If you were really worried about it you could put a resistor between the + and - cables to limit current, but ive never had an issue with it on many different types of vehicles.
Ill give it a try!
 
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