Everyone’s been in the same situation, running late in the morning for work when disaster strikes. Your car won’t start, potentially leading to big repair bills.

If your lights come on, radio works, but you hear a clicking when trying to start the car, you’re in luck! This can be narrowed down to either the battery or starter motor in 99% of cases and is easy to diagnose.

 

Battery

Visual Inspection

First on the list is your battery. Most commonly located under the bonnet in plain view, and in the boot in BMW’s. This is the main culprit for starting issues, commonly caused by a worn-out battery from age. Batteries can last anywhere from 3 years to 10 depending on climate, cold weather is harsh on batteries and will shorten their working lifespan.

Remove any covers to expose each terminal and check for a blue/white crystal substance on each terminal. If you see this do not touch, as it’s battery acid that’s leaked from the cells and will cause chemical burns. Corrosion will look like the image below:

Battery acid leak

Instead mix 16oz (500ml) of hot water (not boiling!) with 1 tspb of baking powder, and slowly pour over the terminal. The mixture will bubble up and fizz, neutralising the acid.

Slowly pour clean water to remove the residual baking powder and dry off with a lint free cloth.

Swelling

Check the rest of the battery for swelling or visible leaks. Inside the battery is a mix of distilled water and battery acid, if this mixture leaks you will see a blue/white crystal substance. Swelling isn’t a good sign either – replace immediately ensuring proper disposal of your old battery.

Terminal Connectors

If there isn’t anything visibly wrong, you now want to check the connections to each terminal are securely attached. To check this, give them a slight wiggle to check for play. You shouldn’t be able to move these connections – if they are loose go ahead and tighten them up.

Check the terminals and connections for dirt and grime, as this can prevent a circuit being formed. An old toothbrush with a diluted baking soda mixture will clean up the connections perfectly.

If you need to remove the connectors, remove the negative terminal (indicated by a -) first, then the positive terminal.

When reconnecting the battery, the positive terminal needs to be connected first (indicated by a +) then the negative terminal.

Multi-meter

You can also test whether the battery has a charge by using a multi-meter. An extremely useful piece of equipment that should be in every DIYers toolbox. If you find yourself without one, I recommend the X.

To use simply turn the dial to X, then wait for the display to zero. Touch the negative and positive terminals to the corresponding terminal on the battery and wait for the number to stabilize.

 

Starter Motor

If your battery passed the above tests, our focus will move onto the starter motor.

If you can hear one loud click or no clicks when turning the ignition, this indicates a problem with the starter solenoid.

What is a starter solenoid?

A solenoid is a coil of wire wrapped into a tightly packed helix shape. This solenoid is then used as an electromagnet, as the device creates a magnetic field from the electric current passed to it when you turn the ignition.

This small surge of current from the ignition turn, creates the electromagnetic field which brings the two connections together, completing the circuit and providing the starter motor with power.

As this is a moving part it’s susceptible to breaking and will eventually need to be replaced. As we can’t provide specific tutorials for each vehicle, I advise you to grab a Haynes Manual which will guide you through the process of replacing starter components.