With my 1980, the power windows have been a source of buying aspirin since I got the vette.
Put power to the window motor and confirm it works. Use a voltmeter and check the harness connector plug for power. Be careful not to damage the connectors in the plug when you insert the test leads. Don't go from one of the leads in the plug to a ground on the car, keep the 2 test leads on the plug. When you work the switch, a digital voltmeter will read power if the switch is working. When the meter shows a negative symbol in-front of the number, it means the polarity reversed for the window to go in the other direction. If you don't get correct power at the plug, you need to check the wiring to the switch.