AC Only Blows Cold When Driving?

If your AC is blowing cold only when you’re driving, the problem could be with the thermostat or the vacuum hose. If your car’s AC only blows cold air while you’re driving and not at a standstill, it’s likely that there’s something wrong with either the thermostat or vacuum hose.

A faulty thermostat can cause your AC to stop working entirely, but if it starts working again once you start moving, then it’s probably just a matter of replacing the part. A defective vacuum hose can cause similar symptoms your air conditioner will stop working at a standstill and resume once you start moving again.

This problem is most likely caused by a crack in the hose or a loose connection somewhere along its length.

The ac condenser is not working

The AC condenser is the part of your car’s cooling system that helps it run. If it’s not working, you’ll notice one of two things either the AC will blow cold air, but only while you’re driving, or it won’t turn on at all.

If you’re noticing the former problem, then there’s a good chance that your AC condenser has failed. This can happen because of age and wear, or because there’s been a leak in your system. Either way, it needs to be replaced ASAP so that you don’t have any further issues with your cooling system.

The blower motor is not working

If your air conditioning only blows cold when you’re driving, the problem may be with your blower motor. The blower motor is responsible for keeping the car’s interior cool and comfortable, so if it isn’t working properly, you’ll notice that the air conditioner isn’t as powerful as before.

The good news is that this problem is relatively easy to diagnose and repair. You can try taking your car into a mechanic or auto shop to have them diagnose the issue for you, but if you have access to the right tools and are comfortable doing some basic maintenance on your own vehicle, it’s worth giving this a shot.

The evaporator coil needs to be replaced

The evaporator coil is the part of your AC system that turns refrigerant into a gas and then changes it back into liquid. In order for this process to work, the coil needs to have a constant supply of coolant from your car’s engine.

When you turn on your air conditioner, the coolant passes through a valve, which causes it to flow through the evaporator coils and be cooled by their fins. This creates a stream of cold air that flows into your cabin through vents in the dashboard or floorboards.

If there is any kind of damage or obstruction in this process, then it will cause your AC system to stop working properly and will also cause problems with heating too.

The battery is not working

The battery is not working when the air conditioner only blows cold while driving. This problem could be caused by a few things. Check to see if there is a blown fuse in the fuse box. If so, replace it with a new fuse of the correct size. If this does not fix the problem, then you may need to replace the blower motor resistor module or the blower motor itself.

Blown fuse or bad fan clutch switch

If your AC only blows cold when you’re driving, it’s likely that you have a blown fuse or bad fan clutch switch. The fuse on the compressor is what provides power to the compressor and allows it to run. If this fuse is blown, then the compressor will not run and your AC won’t blow cold air.

The fan clutch switch tells the computer how fast or slows the fans should be running. If this switch is bad, then the computer won’t know how fast or slow to run the fans and therefore will not be able to regulate airflow effectively.


Your AC might only blow cold air while you’re driving if you have a blocked air filter. This could be due to dirt or other debris interfering with the airflow into the engine and preventing it from cooling down as much as it should which means your AC compressor has to work harder to get the temperature down, which will make it louder.

Steven Hatman
Steven Hatman

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