Instrument bulb lighting...still dim

I don't know what meter you have, or whether it is "auto" ranging

Set to read DC volts, and if manual, pick a scale above 12V, IE 20, if the next range down is 10, etc.

Make sure one meter lead is well grounded, and make sure the park/ dash lamps are on, with the dash dimmer to "full bright" (normally to left, CCW)

Measure first one, then the other end of the short little "inst" fuse which is at one end of the fuse panel.