How do you test voltage to the speedometer?

[cferb]

I'm having trouble pinpointing my speedometer issue. It was intermittent, slowly getting worse, I took it apart trying to fix it, and ended up breaking it:( so I replaced it, and now it isn't working at all, I'm not sure if the new speedometer is bad, or if the wiring is, but I don't know how to test it.

I bought an LED tester for 6 and 12vs and can't find a ground close enough for it to work, I tested the light on something else and it worked, but all the "grounds" I tried didn't do anything. My dad said it might be in microvolts or whatever, so I might need a voltmeter to test it.

Also, do I need to be moving or no?

[jlevie]

With two non-working speedometers, I'd say that you need to be looking at the speed sensor mounted in the rear of the differential.

[cferb]

Changed it. The first one worked, but intermittent, second one not at all, but it could have happened in the time it took to swap.