68 GTS Speedometer doesn't work

The car is not moving?

Not a lot of info to go on.

What have you done to the car lately?
Did the spedo ever work correctly?


As for testing the easiest would be to pull the speedo cable from the trans and look at the cable insert. you might be able to hook it to a drill motor and spin it to see if the speedo moves. Try spinning the cable counter clockwise but be careful you do not pull the inner cable out from the speedo head in the process.