1997 Chevy Astro power windows

Check the 30 amp circuit breaker for the power window, there may be other systems that also use a 30 amp breaker, if their the same just swap them out, see if it makes any difference. Also, with the key on, check for voltage where the breaker plugs in.

If all that checks out, you need to get at the circuits going to the master switch, check for b+ and ground at the master switch. The yellow wire is voltage, you need to have the key turned on to check for voltage. The black wire is ground. If you have good B+ and ground, there may be something wrong with the master switch.