AC Won't Start After Winter? Common in Cold & Dry Zones
Your AC sat dormant for 6+ months. When you flip it on in May, nothing happens. Here's why cold-climate homeowners face this every spring — and what to check first.
Why cold-climate ACs struggle in spring
In Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, the Dakotas, Montana, Wyoming, and Colorado, your air conditioner sits completely idle from October through April — sometimes longer. That's 6 to 7 months of no use.
During that time, electrical components degrade, moisture corrodes metal contacts, and animals may move in. When the first warm day arrives and you switch to cooling mode, the system has to overcome all of that neglect at once.
The good news: most spring startup failures in cold climates are minor and fixable. Here are the 5 most common causes, ranked from simplest to most complex.
5 reasons your AC won't start this spring
Tripped or turned-off breaker
Many homeowners (or technicians) turn off the AC breaker during winter to prevent accidental cold-weather startup, which can damage the compressor. If nobody turned it back on, the system simply has no power.
Check your electrical panel. Look for two breakers labeled 'AC' or 'Condenser.' Flip them on.
Contactor corrosion
The contactor is an electrical relay in your outdoor unit. After 6+ months of exposure to snow, ice, and moisture, the contacts can corrode or pit. When the thermostat calls for cooling, the corroded contactor can't close the circuit.
This requires a technician. The contactor is a quick, inexpensive replacement.
Capacitor degradation
Capacitors lose charge over time, even when not in use. A capacitor that was marginal last fall may not have enough juice to start the compressor after sitting dormant all winter.
A technician can test capacitor strength with a multimeter and replace it in minutes.
Thermostat not switched to cooling mode
This sounds obvious, but it's one of the most common spring 'AC not working' calls. If your thermostat is still set to 'Heat' or 'Off,' the outdoor unit won't receive a signal.
Switch to 'Cool' mode and set the temperature below current room temp. Wait 5 minutes.
Critter damage to wiring
Mice, squirrels, and other animals seek shelter inside outdoor units during winter. They chew through wires, insulation, and even refrigerant lines. When you turn the system on, damaged wiring prevents startup.
A technician needs to inspect and repair any chewed wiring. Check for nesting material around the unit.
Before turning on your AC for the first time each spring, go outside and inspect the unit. Remove any debris, leaves, or animal nesting material. Then turn the system on and let it run for 10 minutes before setting it to your desired temperature. This gives the compressor oil time to circulate.
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