Troubleshooting Tips for Your Car’s AC Unit
There’s nothing worse than your car’s air conditioning calling it quits partway through the summer. But just because your car’s AC unit can’t keep its cool doesn’t mean you have to lose yours.
ATC has put together a list of pro tips for troubleshooting the most common car air conditioning issues. Check them out so you can get your car’s AC back up and running in no time!
On the side of the road is one of the furthest places you can be from the side of the beach.
1. Subpar AC Airflow
If you set your AC to its max setting only to be met with air that’s weak at best coming through the vents, there could be a blockage of some kind obstructing the airflow.
Here’s what to look for:
- Start your car, turn the AC on, and take a look under the hood. Check that the pulley located on the front of the compressor is turning. If this pulley stays in place, the AC’s clutch isn’t engaging. This is most often due to a wiring issue or a bad fuse. If you see the clutch engage and disengage rapidly, refrigerant may be low (see section 3).
- Weak airflow could point to a (very) clogged cabin air filter. Check the cabin air filter. If this is the source of your AC woes, you’ll know it right away. Get a new one put in ASAP.
- Check that the condenser isn’t blocked by any nests, bugs, or leaves.
2. Hot Air Coming Out of Car AC
Refrigerant is the fluid that allows your car’s AC unit to pump out cold air. But a unit that runs on too little or no refrigerant will completely lose its cool factor. If your system is blowing out hot or lukewarm air, it’s likely due to a refrigerant leak.
3. How to Check if Your Car Has a Refrigerant Leak
When air conditioning units are installed in cars, the system is sealed internally and should, in theory, stay that way. But inner AC parts are notorious for getting damaged easily and springing leaks. The issue with a potential refrigerant leak is that once liquid refrigerant escapes the system, it instantly turns into an odorless, colorless gas. So you won’t see refrigerant in a puddle under your car.
The most effective method for determining where the leaks in your air conditioning unit lie is to reload the system with refrigerant and a special dye (available at auto supply stores). After using the unit for a few days (you should have a brief return of cold air), shine a UV light under the hood with the AC running. You should be able to see where leaks are located, highlighted by the dye’s escape points.
Other areas to check/tighten:
- Double check that all fittings are secure.
- Check the Schrader valves.
- Check the compressor’s hose manifolds and any seals to pressure switches on the back.
What Would an ATC Technician Do?
The problem with your car’s AC unit could just be a simple fix or it may require multiple parts to be replaced. Figuring out where the issue is coming from is definitely half the battle.
Students enrolled in ATC’s automotive technology programs get to learn the science behind many of your car’s complex systems and how to keep them working in optimal condition.
Want to learn about how automotive techs handle routine inspections and replacements like these? Download our free eBook that takes you through common shop practices and procedures, including oil changes, tire rotations and balances, battery checks, and many more!
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