It can be very annoying and even dangerous to drive in extreme heat without working air conditioning. If you can determine what the problem is, you can determine if you should take your car to the garage or if you can fix it yourself. And if you do have to go to the garage, you will be less likely to be scammed if you already know what the problem is.
Steps
Method 1 of 3: Gathering the first information
Step 1. Turn on the air conditioner with the engine running
The air conditioner cannot work properly if your engine is not running. Set the blower to 'air from outside' (so no recirculation), open the middle ventilation grilles of the dashboard and turn on the air conditioning.
- Set the blower to the highest setting.
- Use the 'Max AC' setting if your car has that option.
Step 2. Listen for unusual noises from the air conditioner
Weird noises may indicate a problem with the compressor. A repair or replacement may then be necessary.
Step 3. Feel the air coming out of the vents
Try to determine whether the air is cold, room temperature, or warmer than the air present. Also note whether the air is cold at first but then becomes warmer and whether the airflow is warm at short, colder intervals.
Step 4. Note the strength of the airflow
Set the blower to the different positions and determine whether the airflow becomes harder and softer, as you are used to.
Step 5. Smell the air coming out of the vents
A strange smell may indicate a leak. You may also need to replace the cabin filter.
Step 6. Check the fuse
Read the owner's manual to determine where the fuse panel is located. Common locations are under the hood, in the trunk, or at the driver's feet. If your air conditioner stops working, it could be because of a blown fuse.
Method 2 of 3: Diagnosing airflow problems
Step 1. Check all air vents
Determine if air is coming out of the vents you selected with the switch. Slide the switch to verify that the airflow is moving to the correct vents.
- If the airflow remains the same after sliding the switch, there is probably a problem with the air distribution in the ventilation shafts. Then the dashboard will probably have to be partially opened to fix this.
- When you turn the temperature knob, the stove valves change position, so that the distribution between warm and cold air changes.
- Sometimes the air conditioning itself works well, but the cold air is not blown into the cabin. For example, the airflow can be blown into the engine compartment.
Step 2. View your cabin filter
Check the cabin filter if the air from the vents smells strange or if the airflow is getting weaker. It is clear to see if the filter is dirty.
- The cabin filter may have become so dirty that there is hardly any air coming out of the grilles. Moving a cabin air filter is relatively easy and cheap.
- You can probably find how to replace the cabin filter in your owner's manual. If not, search online using the search terms 'replace interior filter' followed by the make, type and year of manufacture of your car (for example, search for 'replace interior filter Toyota Camry 2006').
Step 3. Check for a problem with the fan motor
The easiest way to do this is to turn on the heating. If the airflow becomes weaker with the heater on, the fan motor may be broken.
- If your fan motor only runs on the highest setting, there is likely a problem with the fan resistance.
- It can happen that mice or other rodents build nests in hoses of your car, when you start the car the animal can get into the fan motor. A loud noise (or bad smell) can be a symptom of this.
Method 3 of 3: Diagnosing airflow temperature issues
Step 1. Examine the front of the air conditioner condenser
This is usually located in front of your radiator. Remove any leaves and other debris from the condenser and clean it.
Step 2. Check the A/C compressor (AC pump) under the hood
If the airflow strength is OK, but only hot air comes out of the fan vents, there may be a problem with the compressor. You can easily check whether the clutch is engaged. In most cases you will find the compressor at the front of the engine block, just behind the radiator.
- To check the compressor clutch, the engine must be running and the air conditioning on.
- The compressor looks like a small motor with a large wheel (pulley) on the end. This wheel (the compressor clutch) should turn. If not, it indicates a problem with the compressor.
Step 3. Check the compressor belt tension
The belt should be tight. If the belt has too much slack, you probably need a new A/C belt.
Step 4. Look for leaks in your cooling system
One of the most common problems with an air conditioning system is insufficient refrigerant. The air conditioning system is a closed system, so no liquid should escape. If it does, you have a leak somewhere.
- Look for oily deposits on or around the air conditioning system hoses. Oily spots may indicate a refrigerant leak.
- You can purchase an electronic leak detector, with which you can easily identify smaller leaks.
- There are also test methods that use dye, UV light and safety glasses to find leaks.
- If you find a leak, you'll probably need to take your car to the garage to fix the air conditioner. You will probably also need new parts, because many of the components cannot be repaired or patched.
Step 5. Check for freezing
If your AC starts out cold, but doesn't feel cold after using it for a while, it could be that components are frozen. An abundance of air and moisture in the system can cause components to freeze.
- Freezing can also be caused by a saturated filter drier or evaporator.
- Turning the system off and allowing it to defrost temporarily resolves the problem.
- If the problem persists, the system will need to be flushed or vented with a vacuum pump.
Warnings
- Never add refrigerant unless you are sure that a low refrigerant level is the cause of the problem. Putting too much refrigerant in the system can seriously damage the system.
- It is always better to have your vehicle repaired by a professional.
- Wear safety goggles and work in a well-ventilated area to allow fumes to escape. Never touch your eyes or mouth after coming into contact with Freon or other chemicals. Always wear a long-sleeved shirt and gloves.