How to repair your semi truck AC

Posted by & filed under Trucker's Tips.

It’s the middle of summer. It’s hot. It’s humid. And suddenly, you notice the inside of your cab getting hotter. Your semi truck AC is still blowing, but the air isn’t cold. You know you’re going to have to stop soon for repair. But in the meantime, let’s talk about what may be causing the need for AC repair.

Low freon

Perhaps the easiest fix is freon. This refrigerant is used to keep your vehicle cool, and it will gradually start to run low. You can purchase a few cans of R134 from your local store, as well as a pressure gauge, but you may find it easier to get the proper balance by having a professional recharge your system. After all, when you’re hot and all you can think about is getting cooled off, you may be tempted to aim for a lower air temperature. But if you go too low, the system can literally freeze over and lock up. A professional can balance the pressure, so your system is cooling off your cab with the correct air temperature.

A broken high pressure switch

The high pressure switch helps determine if the proper amount of refrigerant is flowing through the system. In our example at the beginning, the symptoms we described are likely what is going on if the AC stopped working suddenly, despite operating fine during the initial miles of your haul. If the high pressure switch is malfunctioning or even completely broken, the system will be unable to properly cool the vehicle – if it even cools it at all.

Mold, dirt, or other contaminants

The nature of your engine creates an environment that can potentially lead to the growth of mold. It might sound crazy, but if you begin to notice an odd smell coming out of your vents, this could be a sign that mold is actually in your system. Have this professionally cleaned immediately.

Dirt and other contaminants can also mess with your system. Animals can occasionally get under the hood while the engine is off and cause problems that aren’t discovered until later.

A problem with the compressor

Everything from a failed expansion valve to the orifice tube to a broken clutch can cause the compressor to malfunction. A voltmeter can determine if the proper voltage is reaching the compressor, but further inspection can reveal damaged hoses, seals, or even damage to the condenser unit. If any of our aforementioned possibilities have been looked at, and the system is still not cooling your cab, it may be time to have the system professionally inspected.

If you find yourself in need of repairs, as always we’re here to help. Our service and repair division can help get your AC back up and running and you on the road. Learn more about our service division HERE, and stay cool this summer!

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