Troubleshooting After a Serpentine Belt Replacement: AC Not Working?

If your air conditioning (AC) has stopped working after having the serpentine belt replaced, it's understandable to feel a bit frustrated. But don't worry! Below are a series of steps you can take to diagnose and potentially resolve the issue.

Check the Belt Installation

Ensure that the serpentine belt was installed correctly. If it's loose or misaligned, there's a chance it might not be driving the AC compressor properly. Double-check the belt's alignment and tightness.

Inspect the AC Compressor

Look at the AC compressor to see if it's engaging. When the AC is turned on, you should be able to tell if the clutch on the compressor is spinning. If it's not, you may need to check the compressor or the electrical connections for any issues.

Check for Refrigerant Leaks

If the AC system was opened during the serpentine belt replacement, it's possible that some refrigerant was lost. Check for signs of refrigerant leaks or have a professional check the system pressure. A proper Freon charge is crucial for your AC to function effectively.

Examine Fuses and Relays

Check the fuse box for any blown fuses related to the AC system. Also, inspect the relays that control the AC compressor. These components are essential for the AC to operate correctly and should be functioning as intended.

Look for Electrical Issues

There may be wiring or connection issues that occurred during the repair. Inspect the wiring harnesses and connectors for any disconnections or damage. Pay attention to any signs of wear or corrosion that could be causing the problem.

Consult a Mechanic

If you're unable to identify the problem or if the issue persists, it's a good idea to take your vehicle back to the mechanic who replaced the serpentine belt. They should be able to diagnose and fix any issues related to the installation.

Additional Considerations

If by saying 'your AC is not working' you mean it does not blow at all when you turn it on, the problem is probably unrelated to the new belt. If this is the case, the next step is to check the fuses and relays. If there are no blown fuses and your relays are all working correctly, check the system for a proper Freon charge.

If you mean that it blows but the air is not cold, you should start by checking to see if there is a belt around the pulley of the AC compressor. Some vehicles have a separate belt for the AC compressor. If the compressor belt is missing, the compressor won't turn, and the AC will just blow ambient temperature air. If the system is low on Freon, there is a safety switch that will keep the compressor from engaging to avoid burning it up. That switch can also fail if the Freon charge is low. Check the switch to ensure it's working correctly.

When the compressor engages, you can usually hear a change in the sound under the hood. If you can clearly see the front of the AC compressor, check to see if it is engaging. With the engine running, have one person watch the front of the AC compressor while one person is inside the car turning it on and off in four or five-second intervals. When the AC is turned on, you should not only hear the compressor start but also see the part in front of the pulley suddenly start turning. When it's turned off, you'll hear a change, and the front of the compressor will stop turning. If the compressor isn't engaging, the problem is either the AC compressors clutch or something electrical, or the safety switch.

The best thing to do is to go back to the mechanic who did the work and politely ask for help correcting the problem. If it's as simple as a belt routing mistake, the repair should be quick and easy, with a somewhat red-faced technician.

One final thing: It is possible that a particularly challenging belt could have been nudged loose by the mechanic. An easy mistake to make, but an easy one to correct. To avoid this, ensure that all belts are securely installed and properly routed.