67-72 Electric speedo

[plumber452]

Not to step on lutronjim's question but I need help. I just completed my conversion and was able to bench test my dash lights, volt meter , etc. I couldn't bench test the speedo. So, today I layed my new cluster in the seat hooked 12 volt ignition, a ground and the wire coming from the PCM to the speedo and took it out. Nothing. The needle didn't move at all. I then disconnected everything and hooked my meter to the wire from the PCM and test drove it. At idle 0 volts. As I drove the voltage increased to a max of 6.6 volts at appx. 35 m.p.h. Any thoughts? Thanks