I did that in my truck...
Day:
Night:
The way to do it is pull the cluster out, and behind each gauge are pieces of clear plastic that carry the light through them to different points in the cluster, including the gauge needles. Find the ones that go to the needles, and on the surface facing the light bulb, go over it with a red marker. That will turn the light going to the needles red, but won't affect the other lighting.
Take care,
~Chris