Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I presume that you are using this Tech Tip document:
to do the calibration electric, on page 3 of 4. Have you located the three wire/terminals, the Blue, Green, and Red wires? is that where you measure and find nothing?
If so, then check your voltmeter: measure some other voltage of roughly that range of volts.
And, make sure the places where you are measuring are good contacts - not greasy nor oily. (A rub over the spot you place the probe tips on, with a clean rag cloth of any quality, would be worth while as a precaution.)
Then, trace the wires. Check their connection status, that they are connected at each end, and unboken along their entire length.
Make sure the treadmill is indeed at zero incline.
Make sure you take care, but also: you need the machine to have power applied to it! just be careful about what you touch.
I am suspecting, if you go through all that and find out nothing new, and that 0 volts is still measured as present, you may have a breakage, a blown fuse, or a ruined component somewhere 'up the line' from the measurement point.
Let me know how that goes, so far.