Why Does My Car’s AC Stop Working While Driving?

Driving in hot weather can be uncomfortable, and relying on your car's air conditioning (AC) system to keep you cool can be crucial. However, it can be frustrating when your AC stops working while driving. In this article, we will explore the common causes and diagnose potential issues that may be causing your AC to fail.

Compressor Clutch and RPMs

One common issue that can cause your car's AC to stop working while driving is the compressor clutch. If you notice a rise in RPMs, it can lead to a increase in compressor pressure. This may trigger the high pressure cutoff switch, which, in turn, turns off the compressor clutch. This is a safety mechanism that prevents damage to the system from excessive pressure.

High Pressure Switch Issues

The high pressure switch is another critical component that can cause your AC to stop working. If this switch reads either a high or low pressure situation, it can disengage the clutch on the compressor. To diagnose this, you can use a manifold gauge to check the high and low pressures. Many times, the high pressure switch is faulty and needs to be replaced, typically costing around 30 dollars. If you experience any issues with pressure readings, it's advisable to replace this component.

Is the AC Getting Warm?

If your car's AC is warm, there could be a problem with the refrigerant. The AC system should be cold to effectively cool the inside of the vehicle. If the AC is warm, it could mean there is a leak in the system or insufficient refrigerant. However, it's possible that the AC is simply operating on a lower setting, especially if your car is running at higher RPMs.

Comprehensive Causes of AC Failure

Several factors can contribute to your car's AC failing while driving:

Fuses: Blown fuses can interrupt power to the AC unit, causing it to stop working. Switches: Faulty switches can prevent the AC from functioning. Compressor Issues: If the compressor is bad, it won't be able to circulate the refrigerant effectively. Leak: A leak in the refrigerant line can cause the AC to stop working. Refrigerant leaks can be difficult to locate and fix without proper equipment. Fluid Issues: Problems with the refrigerant can cause issues with the AC system.

To diagnose these issues, you should take your vehicle to a certified AC technician who can properly assess the system. Depending on the problem, a simple service might be needed, or the issue could be a complete compressor flush, receiver dryer evacuation, and recharge.

Common Symptoms of AC Failure

If your AC stops working while driving, a few key symptoms can help diagnose the issue. These include:

No Cool Air: If the AC doesn't produce cold air, it could be a sign of a refrigerant leak or a bad compressor. Warm Air: If the air coming from the vents is warm, it could indicate an issue with the refrigerant or the compressor. Belt Issues: If the AC belt has come off, the compressor won't be able to pump refrigerant, causing the AC to stop working. Fuse Issues: A blown fuse can interrupt the power supply to the AC unit, rendering it inoperative. Control Panel Problems: A faulty control panel might prevent the AC from functioning. Check if the heater works to see if the control panel is the issue. Blower Motor Failure: If the blower motor is not working, the AC refrigerant might not be circulating, leading to the AC not cooling.

For a thorough diagnosis, it is highly recommended to consult a professional with the necessary tools and experience to pinpoint the exact issue and provide a solution.