[74shark]

I just got an 1989 corvette and am having problems with
the speedometer. For some reason it will always read zero.
When I turn the key on all the lights for the dash come on so I
know the cluster itself is ok. nothing is dim or burnt out.
The tach and other gauges all work fine. But my speedometer, odometer and trip functions don't work. they all read zero. and the odometer stays at 70,000.
My guess is that the speed senor on the transmission is bad. Just looking to see if I am missing something simple. It looks like the previous owner installed a skip shift plug, I don't know if that might have something to do with it.
I was just wondering if this is a common problem or not.
I tried the search function but could not find many answers.

 

[ex-x-fire]

The gears that drive the speed sensor maybe worn, they are plastic. Remove sensor, keep it plugged in, turn the key on & turn the gear on the sensor while someone watches the speedometer. You may have to use a drill to get it to spin fast enough.

 

[vetteoz]

The gears that drive the speed sensor maybe worn, they are plastic.

I have had the clip that holds the drive gear on the output shaft break so no VSS drive
Vette setup same as pic but has VSS , not early style cable drive as shown

 

[74shark]

thanks

thanks for the help I will check the sensor in the morning.