After 46k miles and 16 years, my speedometer has called it quits. It's a '92 with an electronic speedometer. I've connected to the ECM and I can see the correct speed, so its not VSS. I've pulled dash and tested using this method (posted here before):
The speedo didn't jump with this test, so the problem would be with the gauage console. People seem to just replace the speedo (which aren't readily available) instead of repairing it. Is there a reason for this?


Now, is the problem in the little circuit board or the speedo motor? The circuit board looks pretty simple, but it sounds like there isn't a known common problem with the boards? Cold solder joints, dead diodes, logic chip problem (seems unlikely)?

Or is the problem typically with the motor? Is there a way to test the motor? Is it a stepper motor? Is it a plain motor whose RPM is controlled to simulate a spinning cable? Is the pinout of the motors 4 pins available? Has anyone connected a microcontroller to the motor to test it directly (which uC & where's the code)? I've controlled servos with a rabbit uC, but not a motor.

Thanks for the help!

Joe
'92 Z28
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