so if you want to test the gauges. wire up 2 AA batteries in series.
or take one of the mini flash lights that use 2 aa or aaa batteries and pull the bulb.

wire one from the pos side of the batteries and neg to the posts on the gauge.
should provide 3 volts.
apply power and if they move to the middle, they are still good.

lots of tests you can do without having to send anything in.

but first unless all 3 fried, is unlikely all of them are dead at the same time.
it is more likely either another bad vr, or your wiring pulled back on the cluster and you don't have power to them.