Outdoor Unit Not Running? Start With the Checks That Cost Nothing.

The outdoor unit has its own breaker in the panel AND its own shutoff — the gray disconnect box on the wall beside it. Storms, surges, or landscape work can trip the first or unseat the second. Check the panel for a tripped AC breaker (reset it ONCE), and confirm the disconnect's pull-out block is fully seated. If the breaker re-trips, stop — that's a real fault, and forcing it is how small failures become compressor failures.

Before assuming the unit failed, confirm the call: COOL mode, setpoint 3°+ below room temperature, fresh batteries if yours takes them. A blank or dead thermostat points at low-voltage power — the transformer chain — rather than the outdoor unit itself. Two minutes at the wall settles it.

The Valley's most common summer failure. Listen at the unit while cooling is called: a hum or periodic click with no fan movement means the motors are being fed power but can't start — the capacitor's shove is gone. Shut cooling off and call; every additional start attempt cooks the compressor a little more. Same-visit fix in most cases.

The contactor is the switch that connects household power to the outdoor unit when the thermostat calls. Burned contacts, a dead coil, or — genuinely — an insect body across the contact faces leaves the unit silent with everything else healthy. The opposite failure matters too: an outdoor unit that WON'T STOP running means welded contacts — kill it at the breaker and call.

If the drain pan backed up, the float switch cuts the cooling circuit — indoor blower often keeps running while the outdoor unit stays down. It looks like a mystery failure; it's actually the system protecting your drywall. A humid-day shutdown with water near the indoor unit (or a drip from the little pipe over a window) is this, and the fix is clearing the drain, not bypassing the switch.