Testing Instrument Cluster/Speedometer

Just wondering is there a way to check a instrument clusters mileage on new cars...when the cluster is out of a vehicle using a battery or something?

No the speedometer take the reading from the computer

speedomoters use either a hub-based, transmission-based or differential-based speed sensor. not from the computer. the information may pas through the ECU on way to the instruments, but it can't tell the speed itself.

if you want to know if the speedo is accurate you'll need to test it with a GPS-based system or a rolling road.

if it's mileage you're talking about, then most new digital odometer can't be reset, but old analogue ones can be wound back easily, and there's no way to tell the original or true mileage.

Well you see i need to know if there is a way to see the mileage on a cluster without having to attach it to the vehicle, i dont want to reset it or anything and i dont care if the guages work on not just want to know how much mileage is on the cluster....

you'll have to find the power input on the cluster and connect a battery to it, there's no way to read a digital odometer without providing it power.

you'll have to find a wiring diagram and then narrow-down which wires are the ones providing power. there's no guarantee that'll work, but it's the only way i can think of.