house is 13yrs old

You detached the wires so that there is no load and the breaker still trips? Sounds like someone drove a nail through the cable somewhere.

Thanks for the response. No work has been done to the house lately, and the AC appeared to work fine a month ago.

Not being an electrician... But I assume there are only the 2 wires coming straight from the breaker to the AC unit. It is literally 10ft away on the other side of the garage wall. We did have a rat issue in the garage a couple weeks ago... perhaps it got in the wall near the breaker box?

Also, I pulled the "not a circuit" plug on the outside wall, which again I assume it would prohibit a load on the circuit... Still trips.

Detach the wires from the breaker and see if it still trips. If it doesn't, then something is wrong with the cable.

Got it. Thanks for the advice.

There's no disconnect? Breakers rarely fail but it is possible.

Leave the wires disconnected from the unit and cap them. Disconnect the two hot wires from the breaker and use a multimeter to test for continuity from each wire to ground. If you have continuity, the cable is damaged somewhere. If not, replace the breaker.

Common causes of an air conditioner tripping the breaker include:

https://www.heating-air-conditioning.net/

Dirty air filter

Dirty outside unit

Issue with the circuit breaker

Motor has shorted

Compressor has trouble starting

Compressor is grounded

You can fix the first problem yourself, but everything else requires an AC repair technician.