Why will my AC not turn on?

Check the thermostat and circuit breaker first. Common mechanical causes include failed capacitors and contactors.

How much does it cost to fix?

Costs range from $0 (breaker reset) to $3,000 (compressor). Most electrical repairs cost $100–$400.

You can check the thermostat, replace batteries, and reset the breaker. For internal components, call a professional.

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Diagnostic Guide

Why Your AC Will Not Turn On

AC not turning on? Learn the most common electrical and mechanical causes and repair costs.

When your air conditioner will not turn on at all, the issue is usually electrical.

Common Causes

Tripped Circuit Breaker

AC systems draw significant power. A tripped breaker is the most common cause.

Thermostat Malfunction

Dead batteries or a faulty thermostat can prevent the signal from reaching the AC.

Blown Fuse

The disconnect box near the outdoor unit contains fuses that can blow.

Failed Capacitor

The start capacitor provides the initial surge to start the compressor.

Contactor Failure

The contactor controls power to the compressor and condenser fan.

Estimated Repair Costs

Repair	Cost Range
Circuit breaker reset	$0 (DIY)
Thermostat replacement	$75 – $300
Capacitor replacement	$150 – $350
Contactor replacement	$150 – $400
Compressor replacement	$1,500 – $3,000

Should You Repair or Replace?

Simple electrical components like capacitors are always worth repairing. For compressor failure on systems over 12 years old, replacement provides better value.

See full HVAC replacement cost guide