The headlight bulb receives power from the wire harness. It connects to the bulb’s base from the engine’s power distribution hub. If you’re having problems with your headlights, the first place you might want to diagnose is the headlight wiring and fuse. If the issue is from the wiring, you should consider changing the wiring harness. Like with almost any electrical system, if the wiring is faulty, the system won’t function. This applies to your car’s headlights. The headlights could stop functioning for several reasons, including rodents getting into the hood, chewing on the wires, or a connection coming loose. If you are knowledgeable about using a voltmeter, you can check the headlamp for power to see if a discontinuity prevents the electricity from reaching the headlights.
A replacement wiring harness kit must first be purchased. The precise procedure shouldn’t take too long. Depending on your car’s make, model, and year, the methods described here may change.
Things you’ll need
- Adjustable wrench
- Solder sleeve wire connectors
- Wire cutters
- Electrical tape
- Painter’s tape
- Heat gun
Step 1: Check which headlight is malfunctioning
Turn on the headlights once you’re inside your vehicle. Step outside and look if you cannot determine which headlight is malfunctioning inside the vehicle. Return inside, then off the headlights. As well, switch off the engine.
Step 2: Open the hood
Your car’s hood or bonnet should be opened so you can unplug the negative battery connector. Here is how to disconnect a car battery if you haven’t done it before. You can operate the headlight without the risk of electric shock by cutting off the electricity to your car’s electrical systems. Ensure that the negative terminal is not close to the battery. Painter’s tape can be used to cover its end just in case.
Step 3: Disconnect the wiring harness for the headlights
Reach for the wiring harness and unplug it if you have access to the back of your headlight assembly through the engine compartment. Depending on the securing system used, you should be able to take it out or unclip it.
Some cars might feature headlights that can’t be reached directly above the engine. You will need to take out the front bumper, the wheel fender, or another component from the engine area to obtain access. For greater leverage, you can entirely remove the headlight housing. If you’re having problems, refer to your owner’s handbook.
Step 4: Assess the wiring connections
Check the wiring harness for any rust or colouring changes. Examine the headlight connector closely and look for dirt and debris. The connector may also be burned, indicating that the wiring could not supply the headlight with enough power and overheating. If the connectors are bad, here is how to change your headlight connector.
Step 5: Cut the wiring harness off and strip the wires
Use wire cutters to cut the wiring harness off. Strip the remaining wires after cutting the harness. The rubber coating can be removed in sections of about an inch. Make sure to avoid damaging the wires by doing this correctly.
Step 6: Braid the new wiring harness
With the wiring you just stripped, braid the new electrical harness. Pay special attention to the wire colours because it will help you match the terminals if you do. Merge the neutral wire from the new wiring harness with the existing wiring neutral.
Likewise, with the positive leads. When you’re done, tape the connection with electrical tape. As an alternative, solder sleeve wire connectors can be used, and the connection can be heated using a heat gun to create a solid seal. Repeat this procedure for any more headlamps that might be experiencing wiring faults.
How much does wiring for headlights cost
For most car models, high and low beam headlight wiring costs less than $25. You could incur labour costs of $100 to replace other damaged electrical components connected to the headlights, such as a fuse. Depending on the vehicle’s make and model, the cost to repair the headlight wiring varies.
How long does it take to rewire the headlight harness
Rewiring your headlight harness should take no longer than 30 minutes. This is based on the presumption that no significant engine bay components will need to be removed to access the headlamp. Because different vehicles have different headlight systems, the time may differ from model to model. After rewiring your car headlights, restore the headlight lenses as well. This is to enable the beam from the headlight bulbs to illuminate at its best.