Welcome, and thanks for using Just Answer. I am Cam, and I will do my best to assist you. When you are finished please click on accept only if you are satisfied. I don't get paid unless you do.Please do not accept if you cannot leave positive feedback. I don't know if you are a tech gor a just working on your own vehicle so we may have to fine tune the answer. I only know as much about your problem as you have told me in your post, so my answers will be based on what you tell me so please add all the details you can. About your vehicle,
Simple fix, like a cleaning, no.
This is a very common issue. This is a failure of the motor that moves the needle. They are called a stepper motor. GM is known for issues with them. The fix is to replace that motor. It is soldered to the circuit board of the instrument panel cluster. You can usually get a very inexpensive repair on Ebay. I have seen repairs ranging around the $100 with a lifetime warranty. http://www.speedometerrepairguy.com/ is one such site
That sounds perfect. YOu can get the stepper motors on ebay or the site I mentioned and he may sell the parts by them selves. When you go to put the needles back on, you need to first plug the cluster in with the key off, then turn the key on but do not start. Gauges like the speedo, tach, oil pressure will be at 0. What I do is use the scan tool to command them all off so all the bad ones would be at or the lowest point on the gauge.
IF you replace the whole assembly then you need to get it programmed. Replacements from GM come ready to be programmed with the mileage.
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