As I said in a previous post, I did'nt measure any change but am not 100% sure where I have to place the second probe from the multimeter? Normally you measure voltage parallel to a wire, but I only have one pin which is sticking out of a connector outside the dyno sensor box.
One of these wires will be connected to ground. If you think the black wire is ground work out which pin will connect to the ground wire then put the -ve probe against that and the +ve probe against the other 2 (One at a time). One of these pins should show the supply voltage.