If you’ve already confirmed your AC unit’s compressor is malfunctioning, and it’s not completely shot, know that in some cases, it is possible to fix AC compressors!
Whether you’re a hands-on homeowner looking to handle AC compressor repair yourself or you’re trying to understand what an AC technician is doing during a service call, this guide walks you through how to fix AC compressors step by step, including what you can safely handle yourself and when it’s best to call an HVAC professional.
How to Fix AC Compressors Step by Step:
If your air conditioner isn’t cooling properly and you’ve already ruled out simple issues like a dirty filter or a tripped breaker, a broken AC compressor may be to blame.
AC compressors are one of the most critical—and expensive—components in your air conditioning system. While some compressor failures will require a full replacement, there are ways to fix AC compressor issues without replacing the entire unit. Important: Always turn off the power to the unit before performing any DIY HVAC inspections.
Step 1: Before Attempting to Fix an AC Compressor, Confirm Power Supply & Test Critical Components
What to Do:
- Check the main electrical panel and AC disconnect box to ensure breakers or fuses haven’t tripped.
- Inspect the contactor and capacitor inside the condenser unit.
DIY Possible: It is possible to safely replace an AC capacitor or contactor if you have electrical experience. Use a multimeter to confirm voltage and continuity. Capacitors must be discharged before removal.
Step 2: Inspect & Clean the Condenser Coils
What to Do:
- Remove the access panel and clear debris from the condenser coil fins using a soft brush or vacuum.
- Spray with coil cleaner and rinse with a garden hose (avoid pressure washers).
DIY Friendly: This is one of the safest and most effective ways to fix AC compressors by reducing strain and restoring performance.
Step 3: Check the Compressor’s Start Relay
What to Do:
- Locate the start relay (usually near the capacitor).
- Test the relay for continuity using a multimeter.
- Replace if it shows no continuity or rattles when shaken.
DIY Possible: Start relays are typically plug-and-play, but it is critical to double-check your system’s model-specific wiring before attempting to replace or fix AC compressor components.
Step 4: Test Refrigerant Pressure
What to Do:
- Hook up refrigerant gauges to the low and high side service ports.
- Compare pressure readings to manufacturer specifications.
- Low pressure may indicate a refrigerant leak; high pressure may signal blockage or airflow problems.
AC Repair Professionals Only: Refrigerant testing and handling require EPA certification. It’s illegal to recharge refrigerant or fix leaks without a license. Call a professional for this step.
Step 5: Look for Mechanical Obstructions
What to Do:
- Listen for clicking or humming sounds when the compressor tries to start.
- Another important step when trying to fix AC compressors is to check for signs of a seized compressor motor (e.g., stuck rotor, burned insulation, or vibration but no rotation).
AC Professional Recommended: Internal compressor repairs (like replacing bearings or pistons) require full disassembly, vacuum pumping, and refrigerant recharging—not DIY territory.
Step 6: Replace the Compressor (If Compressor Repair Isn’t an Option)
If all electrical and mechanical components check out, but the compressor still won’t start or is locked up, a full replacement may be necessary. However, as discussed in our previous blog, a complete replacement isn’t always the only option, depending on the age and condition of your air conditioning system.
Strictly Pro: AC compressor replacement involves brazing refrigerant lines, vacuum-sealing the system, and ensuring proper charge and oil levels. This work must be done by a licensed HVAC technician.
How to Fix AC Compressors & When to Call a Pro
| Compressor Repair Task: | DIY Safe? | Tools Needed: |
| Replace the capacitor/contactor | ✅ | Multimeter, screwdrivers |
| Clean condenser coils | ✅ | Coil cleaner, garden hose |
| Replace the start relay | ✅ | Multimeter |
| Test refrigerant pressure | ❌ | Manifold gauge set |
| Fix refrigerant leaks | ❌ | EPA certification required |
| Internal compressor repair | ❌ | Professional equipment |
| Full compressor replacement | ❌ | Brazing torch, vacuum pump |
Hiring An Expert to Fix AC Compressors Is Always Ideal
Learning how to fix AC compressors step by step can help you troubleshoot common AC issues and handle basic repairs like cleaning or replacing small components. But when refrigerant, internal damage, or motor failure is involved, it’s time to bring in a certified HVAC technician.
If you’re unsure about any step or don’t have the proper tools, don’t risk further damage. Call a licensed AC repair tech to diagnose and fix the compressor correctly!
Contact CTR Services today at 254-545-1759 for fast and professional air conditioner repair services.
