Speedo went out on my GMC, per a little research, trouble pointed to stepper motor replacement for the gauges and a known common problem. Watched Youtube video on replacement which seemed like no big deal, I work in a test lab and perform soldering on instrumentation so the repair didn't seem to hard. The speedo motor felt skratchy so all was lining up as a bad stepper motor. Installed the new motors, all silky smooth and reinstalled the cluster. Speedo still didn't work when reinstalled. Disassembled, checked solder joints and plugged the cluster back in. Once energized, the speedo stepper motor feels scratchy but when unplugged, smooth as silk. Seems to me the motor is getting a "dirty" signal? The truck runs great, odometer and other mileage related functions work great but the speedo was wonky when I received it last winter. Anyone have any insite on this era instrument clusters? Thanks for any assistance
Just swapped around 2 of the newly installed stepper motors and the problem followed the new stepper motor. I was sent a bad new stepper motor. Gages fixed, speedo working again. If you have this problem, pretty easy fix (unless you get a bad new part).
There were lots of issues with those clusters. Speedos, tachs, gauges, shift indicators, and or dash lights. GM was replacing them for free prior to their financial troubles. Not a true recall. Just replaced for free when defective.
-- Edited by JC2+2 on Tuesday 5th of December 2017 08:59:13 PM
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'68 Parisienne 2+2 Convertible Matador Red (Resale Red but not for sale).
