Why is My Car Air Con Not Working

This is a question we hear every day, “Why is my car air con not working?”

Unfortunately, it’s not a simple answer. It could be a number of things such as:

> Lack of refrigerant

> Fan not working

> Faulty Compressor (or air con pump)

> Damaged Condenser (air con radiator)

> Pressure Switch is faulty

> Leak within the system

> A simple fuse or relay not working etc

Typically you don’t use the car air con all winter (you should do – but more on that another time) and the first hot day of the year comes along and nothing happens, you’re still hot. Where’s the cold air you scream? Kids in the back seat getting loud and agitated, you getting agitated, stuck in traffic with the windows open instead and sticking to your seat, no breeze. Nasty.

So what’s happened?

Why is there no cold air? Or why is there a squealing noise coming from somewhere in the engine?

Well, first thing to check, and often the main cause of no car air con, is lack of refrigerant. Since 1993, give or take a year or 2, your car air con has used a refrigerant gas typically known as r134a. You’ll see stickers in the engine bay with it on; normally.

More recently car manufacturers are using a new, environmentally friendly refrigerant called r1234yf, so over the next few years more cars will be using that instead. Maybe, as there are issues with that. Another story. So, it may be a simple case of lack of refrigerant. It changes state between a liquid and a gas so over a year your car air con will typically lose around 15% of its refrigerant (gas) naturally. After 3 years therefore almost half the gas has gone, so you’ll notice it may not be as cold in the car as it used to be. In which case, it might just need a simple recharge, or regas as sometimes known to bring it back up to normal levels and at the same time check everything else is working, refresh the A/C oil etc. We offer this service via our Cool Car website where we can also change and fit new air con parts if needed and even better; we come to you at home or place of work.

What else could it be?

Aside from losing gas naturally, you may have a leak. You’ll perhaps notice that if you had the cars aircon recharged not long ago and now all of a sudden its not working again. So as part of getting the A/C checked and recharged, a reputable and qualified technician (see Cool Car) they will check for leaks using a UV dye, so you can physically see where the leak is coming from. As is often the case the condenser (the air con radiator at the front of the car) can get stone chip damage and the small hole it makes is big enough for the gas to escape. This then needs replacing. We sell thousands here for all makes and models of car with 2 years warranty. So using an ultraviolet light you can trace the aircon system and find any leaks.

Beside the gas issues, it may be the case your car does have enough gas, but still doesn’t work. So what else could be wrong?

I would suggest next to check the compressor, otherwise known as the air con pump. With the aircon on, make sure it has power. If not then there could be electrical issues such as a fuse, or relay, and it would also be worth checking the pressure switch to ensure that is not faulty. The pressure switch checks to see if there is enough pressure in the system or not and then tells the compressor to work.

If the compressor has power, and there is enough gas in the air con system, then it could be a faulty compressor. They can seize through lack of use, lack of oil etc. Usually if the compressor is receiving power and not working it needs replacing. It is worth bearing in mind that many compressor faults are caused be faults within the air con system, and that simply replacing it will not solve the problem long term and the problem may come back very quickly unless the original fault is found.

But you should also get the fans checked. The fan at the front of the car that usually spins when idle. On some cars one is for the aircon, and another for the radiator, and if the aircon one is not working, it might be stuck for example, then that will cause problems with the aircon as the pressure will get too high.

In summary in 80% of cases it is a refrigeration issue, or lack of it, either naturally or from a leak. Failing that its likely to be a compressor fault. But before you go and start getting parts bolted on to your car, get it checked properly.