The connectors to disconnect power and antenna leads are inside the engine compartment aft of the inner fender liner or perhaps tucked into an opening where the wires come out. The antenna lead is a round coax cable like a TV cable. The power wires are right next to it. I have done this same thing. It is easy to do with just opening the hood, finding the wires, and figuring out out to unlatch the connector. Replacing the whole power antenna unit requires removing the bottom bolts of the outer fender, including behind the open door, and fender lip chrome trim, the idea being to separate the outer and inner fenders and reach up from below to work on the antenna.
If (when) kids break your antenna off you can stick a potato on there.
No need for the potato if the power antenna is just stuck. I had a friend with a 1985 Cutlass and the antenna motor kept running, but the antenna didn’t go down. I pulled the fuse controlling the motor, but it also shut off the dome lights. I pulled the kick panel on the right side of the car under the dashboard and disconnected the lead going to the antenna motor. I replaced the fuse and my friend ran the antenna up and down manually. The replacement of the motor involved removing the fender panel–this was the quick and dirty way out.
Thanks for the clarification on the Cutlass. The first time I heard this on the show I thought the caller had a Custom Cruiser (B-body) but after hearing again I think she said Cutlass. Your advice on finding the connector will useful if she happens to read this.