Overcome alternator malfunctions

When your alternator begins to fail it can cause a variety of different electrical problems in your car, and eventually cause a breakdown. Photo by David Mukooza

What you need to know:

  • According to Thomas Kayinja, a mechanic at Grace Lubega Motors in Makerere, Kampala, the alternator is responsible for generating the proper amount of electricity for powering the vehicle’s electrical components and battery.
  • The alternator is able to generate this power by converting the vehicle’s mechanical energy into electrical energy.

Jonah Musamali’s car had always failed to start even after being assured that his battery was fine. When he decided to engage his mechanic, he found out that the alternator had a malfunction, the reason his car always failed to start, especially in the morning.
According to Thomas Kayinja, a mechanic at Grace Lubega Motors in Makerere, Kampala, the alternator is responsible for generating the proper amount of electricity for powering the vehicle’s electrical components and battery. The alternator is able to generate this power by converting the vehicle’s mechanical energy into electrical energy.
Therefore, if you have a bad alternator, then all your vehicle’s electrical components would need to depend on the battery for power, yet it is not being recharged because the alternator is faulty. Unfortunately, the battery is not powerful enough to provide the proper amount of electricity that these components need. Kayinja says this is why your car may run for a couple of minutes before the power dies. That is why a functioning alternator is a must for any vehicle. Here we take you through some of the causes of car alternator malfunction.

Worn out
According to Bosco Kigongo, a mechanic, the typical lifespan of a new alternator is between five to seven years. However, he does not limit it to these and says it can go beyond but if it has been that long and you have electrical issues, then your alternator is simply worn out and needs to be replaced. If you think it could be your battery that is faulty, the typical lifespan of a battery, according to Kigongo, is between two to five years.
However, he argues that environments that are usually hot will drain the battery power quicker, so it may not go beyond two years in this case. The temperature should not affect the alternator, though.

Computer problem
Kayinja says there is a lot of technological development in the automobile industry and newer model cars are built with computer systems in them. These systems are what manage virtually every component of the vehicle, including the alternator. If there were to be a problem or glitch with the computer system, it could stop the alternator from charging properly even if it is a good alternator. Chances are other issues that would arise from a computer problem too. That is how you would know that was the cause.

Wiring problems
Kigongo says there are lots of wires in the vehicle which deliver power to the alternator. If one of these wires were to become damaged or worn out, then it could cause the alternator to fail and the battery to not get charged. If you do not see any of the other problems on this list being present in your vehicle, then check the wiring of the alternator because that may be the reason for the alternator not working.

Bad fuse
Some vehicles use fuses to keep the alternator functional. These fuses blow out after a while or when there is a power surge. In these cases, Kayinja says your alternator would fail and your battery would not charge. If you have a bad alternator, check the owner’s manual to see if there is a fuse in your car. If so, then see if it is blown.

Broken belt
Kayinja says alternators use the mechanical power of a belt and pulley to generate the electrical energy for the vehicle. The problem is that belt and pulleys are not too durable, which means they can break easily. Pulleys will typically last for a long time before they eventually get damaged from old age. Belts are flimsier and will break after getting stretched out enough times. If either one of these things were to happen, there would be no mechanical energy being generated for the alternator to convert.

Replacement cost
According to Bosco Kigongo, a mechanic, the best option you can do with a bad alternator is to replace it with a new or used one. However, he advises that a second hand, preferably Japanese make, will work efficiently. For big cars such as the Prado TX, Super custom, the second hand alternator will cost between Shs250,000 and Shs300,000 and for the smaller cars such as Spacios and Premios, the price reduces to between Shs150,000 and Shs200,000 depending on the vendor. He adds that the labour costs are negotiable with your mechanic but advises drivers to choose the best.