AC Not Turning On in Los Gatos

AC Not Turning On in Los Gatos

Most no-start calls come down to a single failed electrical component, not a dead system. A run capacitor that lost its charge, a contactor whose contacts burned, a thermostat with no power, or a tripped breaker will each keep a unit silent while the compressor and coil are still good. We work from that and confirm it with a meter.

Los Gatos makes this trickier because a lot of the hillside homes run on more than one zone, with separate equipment for different floors, and some lean on a ductless head for the worst west-facing rooms. So "the AC won't turn on" often means one zone or one mini-split head is dead while everything else cools normally. We pin down which piece of equipment is actually out before we open anything.

Elevation drives the load here. A west-facing upper-level master can be calling hard at 4 PM while the lower family room sits in shade. Equipment that works that hard on the sun side wears its contactors and capacitors faster, which is why the hot zone is usually the one that quits first.

Common causes

Failed run capacitor on the hardest-working zone. Capacitors degrade with heat and load, and on a hillside home the west-facing zone runs hottest, so its capacitor tends to go first. The unit hums or clicks and won't spin up. We meter it against its rating and replace it. Parts ride on the truck for common sizes.

Burned contactor. The contactor's contacts pit from cycling and eventually fail to pass high voltage to the condenser. On a multi-zone home one outdoor unit goes dead while the others run. We test for voltage across it and swap it if it's the fault.

Dead ductless mini-split head. Problem rooms here often run on ductless heads. A head that won't start can be a remote with dead batteries, a tripped condensate safety, or a communication fault back to the outdoor unit. We diagnose the head and the line set rather than guessing at the indoor unit alone.

Tripped breaker or pulled disconnect. Each zone's condenser has its own breaker and outdoor disconnect. A tripped breaker or a disconnect left pulled after work on the hillside kills that zone outright. We check these first since the fix is free. A breaker that re-trips means a real fault, and we trace it instead of resetting blindly.

Thermostat or low-voltage fuse. Multi-zone homes have multiple thermostats and control boards. A dead stat or a blown 24-volt fuse on one zone's board leaves that zone with no cooling call while the rest of the house works. We confirm stat power and check the control fuse on the affected zone.

Tripped condensate float switch. Condensate lines clog, and tight retrofit installs make it worse. A full pan trips the float safety and shuts the unit down on purpose to prevent water damage. We clear the line, flush the trap, and confirm the switch resets.

How we diagnose it

• Identify exactly which zone or head is down, since a multi-zone home rarely fails everywhere at once.
• Confirm power to that zone: breaker, disconnect, and the 24-volt control fuse on its board.
• Read the capacitor and test the contactor on the affected outdoor unit.
• On ductless heads, check the remote, the condensate safety, and communication with the condenser.
• Write up the diagnosis and repair options before any work begins.

$75 diagnostic, credited toward any repair over $200. You get a written quote before any work begins.

AC Not Turning On in Los Gatos: common questions

Nearby and related

AC Not Turning On near Los Gatos: Saratoga · San Jose · Cupertino .

This is usually a ac repair in Los Gatos job. See our ac repair overview or the Los Gatos service area.