Can a Bad Relay Drain Your Battery? Checking and Fixing the Issue

Obviously, a bad relay can drain your car batteries when it doesn't cut power when it should and leaves the power to remain active on many components of the car, even when it's turned off. The role of the relay in your car is important, and it is the factor that power all systems of your car.

Battery drains highlights

• Level of importance:high
• Methods to locate:disconnect everything that can cause drains
• Consequences:dead battery
• Prevention:driving style adjustment, no extra equipment
• DIY fixes:possible but complicated
• Price to fix:$100 - $600

Relay and how it works

Before we discuss how to tell if your car relay is faulty, let's cover what it is and how it works. Relays are electrical switches that control a larger electrical load and reduce the amount of electric current that flows through a particular circuit in your car. Because your car takes a lot of amperages to function, switches can burn if the car operates without a good relay.

Let's break it down into its components and operation to understand how a relay works. A car relay works like a switch controlled by electrical power, and it consists of electromagnetic coils, armatures, sets of contacts, and mechanical switches. Whenever you turn on anything in your car that requires current, it passes through the relay where the armature is attracted, and two pints of contacts close to allow the current to flow.

However, if the current flow is interrupted, the magnetic field will collapse and break the load circuit. There are different types of relays, and among them are; electromechanical, solid-state, and thermal relays. They all serve different purposes and help electrical components in your car to operate efficiently.

Symptoms of a bad relay

In many cases, it's important and easy to identify a problem with your car's relay. To help you recognize and pinpoint its issues, here are some of the symptoms and signs of a bad or faulty relay. Identifying them will help you take appropriate action and prevent potential problems in your car.

1. The battery is draining quickly

The battery of your car draining quickly is another symptom of a bad relay. When there is a bad relay, it may lead to some components of the ignition system to remain on and working. This will cause the battery to drain faster and frequently lead to dead batteries.

2. Your car is not starting or stopped working

One of the most common symptoms of a faulty relay is your car not starting, or it stops working while operating. If the relay is faulty, perhaps it is burnt or corroded; your car will have difficulties starting as it will disrupt the power supply to the ignition system.

3. Your car is facing electrical issues

Another common symptom of a bad relay is your car experiencing severe electrical issues. This can happen due to excessive electrical load, which can further result in flickering dash lights. Do not take it lightly if you notice any of these unusual problems in your car.

You can pay attention to these common symptoms to figure out a bad relay.  Other symptoms which are not explained here and worth paying attention to are headlights flickering, unusual sounds, and frequent blown fuses. Keep reading to learn how to check if your car relay is faulty and how to identify and resolve any problem that might arise.

Checking for bad relay

If your car's batteries are draining quickly or aren't working, and you assume the relay is bad, it's important to confirm and replace it if your assumptions are right. Are you trying to confirm that now? Hold back! Before inspecting, ensure the car is turned off, and the key is removed. Safety comes first, last, and always. Below are steps to help you through the inspection.

1. Identify the relay location

Start your checking by consulting your car's user manual. In case you are not sure about the location, look for diagrams online to find the relays. You will likely find relays inside a fuse box under your car hood.

2. Inspect the relay visually

When you get the relays' location, inspect them thoroughly for any signs of damage or overheating. Try to pay attention to signs of burnt contacts, corroded terminals, or water ingress. In addition, faulty relays with burnt contacts can have burning, so pay attention to smell too.

3. Test the relay with a multimeter

If inspecting visually doesn't help, the next step is to test the relay using a multimeter. Get the necessary tools, such as a multimeter, relay puller, or pliers. Follow your car manual or any reliable instructions to test the relay's contacts with a multimeter. If the relay fails to click or the resistance reading is higher than expected while doing the testing, your car's relay is likely faulty.

Fixing and replacing a bad relay

Once you confirm that your car's relay is faulty, immediate action is required to ensure the appropriate performance of your car and for your personal safety. To properly resolve the issue, it is advised to have the relay replaced, if necessary, by a skilled expert. This will help avoid future car battery drains and electrical issues. Below is a comprehensive guide you can follow to replace a bad relay:

1. Gather the necessary tools

Prepare the required tools for the replacement, including a new relay and socket wrench or screwdriver. Get a quality relay, a replacement of the same type and specifications as the old one, from reputable manufacturers.

2. Disconnect the battery

Start by turning the ignition off before disconnecting your battery. Never try to disconnect your car's battery while the power is on. You then disconnect the battery's negative terminal to ensure safety when you're replacing the bad relay. After that, repeat the same process for the positive terminal.

3. Remove the faulty relay

Once you disconnect the battery, locate and carefully remove the bad or faulty relay from its socket with the help of a relay puller or pair of pliers. Because you will be installing a new one, take note of its orientation for its correct installation.

4. Install the new relay

Once you remove the faulty relay, insert the new one into the socket. Lastly, make sure that the new relay's orientation matches the old one.

5. Reconnect the battery

After the whole process, you can now securely reconnect the battery's terminals. You then test the new relay's functionality to verify if the issue has been resolved. Once this is solved, you can bid goodbye to battery drainage.

While you can fix the relay by yourself, there are also chances you won't be able to do this and hence cause further major issues for your car. If you feel that you can't handle the fixing of your relay, don't hesitate to call a professional mechanic or technician to inspect your car. Read on to get further information on how to prevent issues related to bad or faulty relays that may arise in the future.

Preventing relay issues

While relays can fail over time due to wear and tear, there are measures you can take to prevent relay issues in the future:

1. Service the electrical system regularly

Follow the manufacturer's recommended maintenance schedule for your car's electrical system, including checking and cleaning the relays.

2. Protect relays from excessive heat and moisture

Always try to protect the relays from extreme temperatures and moisture, as these factors can contribute to their premature failure.

3. Avoid overloading the electrical system

Be mindful of adding excessive electrical accessories to your car, as it can strain the relays and lead to failures.

Final takeaway

In this blog, we have understood what relay is and how a bad version can further affect your car battery through draining. Your car gives so much and asks for so little. The little it requires from you is to pay proper attention and give it the needed maintenance. Failing to do this causes a bad relay to become one of the unrecognized factors that drain your car battery.

Therefore, you need and should pay attention to the symptoms discussed in the article as much as you can. In the event that you notice any of them, do not fail to take immediate action.  Replace the bad or faulty relay to address battery drain issues and ensure your car functions as it should. Do not hesitate to seek the assistance of expert mechanics to help you diagnose your car's relay problem and provide solutions if required.