Dummies' Guide - How to Replace Wiper Blades and Headlight Bulbs Yourself

Wiper blades and headlight bulbs are two of the easiest repairs to do yourself, and they're two of the most common reasons a car fails a WOF. Both jobs take minutes and need almost no tools. The trick is buying the right part, and a couple of small habits that protect your windscreen and your new bulbs.

Part 1: Wiper Blades

When to Replace Them

Replace wipers when they streak, smear, chatter across the glass, or the rubber is split or perished. In the sun and salt air of New Zealand, rubber wears quickly, so roughly once a year is a good rule of thumb, and sooner if you notice a problem.

Find the Right Size

• Look in your owner's manual, or look up your car in a parts catalogue.
• Or measure your old blades.
• The driver and passenger blades are often different lengths, and the rear wiper, if you have one, is different again.
• Check the way the blade attaches to the arm. The most common type is a hook, but there are pinch-tab, pin and side-lock fittings as well. Take your old blade to the shop if you're unsure.

How to Change Them

1. Lift the wiper arm away from the windscreen until it stands up by itself.
2. Lay a folded towel on the windscreen below the arm. If the arm slips and snaps back, the towel stops it cracking the glass.
3. Press the small release tab on the blade and slide the blade down and off the hook.
4. Slide the new blade on until it clicks.
5. Lower the arm gently back on to the glass. Don't let it drop.
6. Repeat on the other side, then test with washer fluid.

Quick tip: While you're there, clean the windscreen and wipe the new blades with a damp cloth. It helps them clear the glass cleanly.

Part 2: Headlight Bulbs

Find the Right Bulb

• Bulbs come in different types, with codes such as H4, H7 or H11, and they aren't interchangeable.
• The type is in your owner's manual, on the old bulb itself, or in a parts catalogue.
• Note whether it's a low beam, a high beam or both, and buy the same wattage.

How to Change One

1. Switch everything off, and let the bulb cool if you've just been driving.
2. Open the bonnet and find the back of the headlight. On some cars you'll need to move a cover or an air box.
3. Unplug the electrical connector from the bulb.
4. Release the bulb. Most twist out, and some are held by a spring clip.
5. Fit the new bulb, handling it only by its base.
6. Reconnect the plug, and test the lights before you put everything back together.

Don't touch the glass of a halogen bulb with bare fingers. The oil from your skin can create hot spots on the glass and make the bulb fail early. If you do touch it, wipe it clean with a lint-free cloth.

Replace in Pairs

Headlight bulbs tend to fade at a similar rate, so it can make sense to replace both at once. That keeps the beams even.

When It's Not a Quick Job

On some cars, getting to the bulb means taking off the bumper, a wheel arch liner or the battery. If it's more than a few minutes' work, or you're not comfortable, get a workshop to do it.

A Word on LED and HID Conversions

Fitting LED or HID bulbs into a housing designed for halogen bulbs can scatter light and dazzle other drivers, and it can fail a WOF. If you want brighter lights, choose a kit that's properly designed for your car, and check with the inspection station first.

Other Bulbs to Check

• Brake lights, indicators, reversing lights and the number plate light.
• Have a friend watch while you press the brake pedal, or reverse toward a shop window.

Read our WOF guide to see how lights, wipers and washers fit into the inspection.

This guide is general advice. Always follow your owner's manual for your car.

Need the Right Part?

Not sure which blade or bulb fits? Request a Part and tell us your vehicle and licence plate. We'll source it or follow up with options. Need a hand fitting it? Visit Our Workshop.