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Volkswagen Jetta Auxiliary Fan Assembly

Ways to Check Your Volkswagen Jetta Auxiliary Fan Assembly for Possible Problems

As a supporting component to the other car parts, the Volkswagen Jetta auxiliary fan assembly is a dual-purpose component that functions depending on its speed. At low speed, it cools the AC condenser when it is overworked or when it has reached a certain temperature. Then, when the engine needs to be cooled down, that's when the auxiliary fan notches up to higher speeds to cool down the radiator. Because of its functions, you can notice when this component starts to fail. When you notice that there is something wrong with the air conditioner, the engine, or the radiator, then it's time for troubleshooting. Here are some ways to diagnose your car's auxiliary fan assembly.

Visual inspection

The first step to finding a problem with your auxiliary fan assembly is to observe the component and its connections. First, make sure that the fan blades are clear of all obstacles and can turn freely. The auxiliary fan assembly's position tends to make them subject to debris collection. Also, check the 10-amp fuse marked "air cond" as well as the one marked "rad fan" on the relay box cover. If one of them is blown, replace it with a new fuse immediately.

System check

When doing a troubleshooting on the auxiliary fan assembly, you should not only focus on the component itself-it's highly recommended that you check the whole system as well. Remember that if one part is going faulty, it could be caused by another component. You can use a thin piece of cardboard in order to force the air conditioning system to behave under the non-speed sensitive conditions. Slide an unfolded cereal box down between the radiator and A/C condenser-found just in front of the radiator fan-to block airflow from the engine fan or puller. If you are doing a system check on a hot day, partially obstructing airflow will do the trick. On the other hand, if it's on a cool day or if your system is still efficient, then it is more necessary to remove the two top radiator brackets. This will completely block the airflow across the entire radiator.

Circuit test

This is quite a common procedure especially if you have been modifying your car. When doing a circuit test, it is important that you have a visual reference specific to your car's model year. To test an auxiliary fan motor, unplug the electrical connector attached to that component. Then, use fused jumper wires to connect the battery power and ground directly to the fan. If the auxiliary fan does not operate, then you have to replace the motor.

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  • Tips on Keeping Your Volkswagen Jetta Auxiliary Fan Assembly Efficient 27 February 2013

    The Volkswagen Jetta auxiliary fan assembly is responsible for cooling down the different parts of your car to keep them running efficiently. This is why it is very important that you keep this component well-maintained; otherwise, the parts that it supports will start to fail. If you don't know where to start with your maintenance, then follow these tips.

    Lubricate the bearings of the auxiliary fan assembly.

    If you can hear a noise coming from the fan even when you spin it by hand, then the component's bearings must have dried up. Remember to detach and disassemble the auxiliary fan first before cleaning. You can use a brake cleaner to remove the old grease and grit. Clean the bushing or oil-impregnated bearing and stator shafts as well. Just put a few drops of transmission fluid in the bushing area and a little grease on the stator shafts. Pack the ball bearing with grease as well, and use a little more grease on the spacer to act as a seal.

    Visually inspect the entire cooling system.

    Because the auxiliary fan assembly is a supporting component to the rest of the system, it is important to keep the other parts in the cooling system well-maintained for it to function efficiently. For starters, check the auxiliary fan if it is free of leaves and road debris. Then, examine your coolant for brown, foamy residue as this might be the cause of a cracked cylinder head. You should also have your car's radiator pressure checked at a local shop if you haven't done so recently.

    Test for power supply.

    Make sure that the cooling system is getting enough power by testing the relay box with a voltmeter. First, you will have to remove your radiator fan relay. Then, with the ignition on, check for battery voltage at the two terminals that are facing the driver's side headlight. Place the black probe on any ground and then check each terminal with the red probe.

    If you don't have a voltmeter, you can also use a test light by clipping the lead to ground and then touching each terminal using the probe. The test light's brightness level is somewhat similar to what you see with a battery test.