If your car is showing strange electrical problems, rough running, or refuses to start, you might be dealing with a bad engine wiring harness. This crucial component connects your vehicle’s electrical and sensor systems, making it essential for proper engine performance.
Replacing an engine wiring harness isn’t a quick fix—it can take as little as 1 hour or as much as 15 hours, depending on the make and model of your vehicle. On average, engine wiring harness replacement costs between $700 and $1,800, with most drivers paying around $1,100 for parts and labor.
Knowing how long an engine harness lasts, the symptoms of failure, and what affects the cost can help you make an informed repair decision and avoid unnecessary expenses.
The lifespan of a wiring harness depends on several factors:
- Material quality – Higher-quality copper and insulation last longer.
- Manufacturing process – Better production methods reduce weak points.
- Environment – Extreme heat, cold, or humidity can cause faster wear.
- Usage patterns – Heavy use, frequent repairs, or accidents can damage wires.
In many cases, an engine wiring harness can last the lifetime of the vehicle. With proper care and without exposure to extreme conditions, they can endure 15–20 years or more.
How Much Does It Cost to Replace an Engine Wiring Harness?
On average, engine wiring harness replacement costs around $1,100.
An engine harness replacement typically costs $1,100. The cost of this repair might vary from $700 to $1,800. The average cost of the part is $650, and installing an engine harness will cost you $575 on average in labor costs. The year, make, and model of your car will all affect how much an engine harness costs. The cost will also be influenced by the features, sensors, and capabilities of your car.
Typical breakdown:
- Parts: ~$650
- Labor: ~$575
However, prices can range from $700 to $1,800 depending on:
- Vehicle year, make, and model
- The complexity of the harness (features, sensors, and capabilities)
- Labor rates in your area
Symptoms of a Bad Engine Wiring Harness
A failing wiring harness can mimic many other car problems. If you notice these signs, have your mechanic check the harness before replacing other parts:
- Intermittent electrical issues – Lights flicker, gauges stop working, or electronics cut in and out.
- Engine performance problems – Misfires, stalling, or loss of power without a clear mechanical cause.
- Starting difficulties – The car cranks but doesn’t start, or starts only intermittently.
- Check engine light – Often caused by faulty sensor signals from damaged wiring.
- Burnt smell or melted insulation – Can indicate overheating wires or short circuits.
- Visible damage – Frayed, cracked, or corroded wires under the hood.
Why Wiring Harnesses Matter
Your engine wiring harness is like the nervous system of your vehicle. It delivers power and communication between components. While they don’t fail as often as other parts, a faulty harness can cause:
- Hard starting or no start
- Loss of power
- Engine misfires
- Sensor failures
If your vehicle is running poorly, it’s worth having your mechanic check the harness. Catching issues early can save you time, money, and frustration.
Bottom line: A good harness can last decades, but if it fails, replacing it is a labor-intensive and sometimes costly job. Knowing the signs of trouble can help you stay ahead of problems.
Wrapping up…
Engine wiring harnesses are crucial even if they might not have as many issues as other car components. It is your car’s brain, and when it malfunctions, it can lead to problems. It’s worthwhile to have a look at your car if you’ve observed that it’s running slowly. You never know when a wire harness issue may arise. Your mechanic can assist you in determining what is required.
FAQs
Can I replace an engine wiring harness myself?
Yes, but it’s not recommended unless you have advanced mechanical and electrical skills. Wiring harness replacement involves disconnecting multiple sensors, connectors, and modules. A mistake could damage the vehicle’s electronics.
Is it worth replacing a wiring harness?
Yes—if your harness is damaged, replacing it can restore engine performance, prevent further electrical issues, and extend the life of your vehicle
How long does it take to replace a wiring harness?
Depending on the complexity of your vehicle, replacement can take 1–15 hours. Luxury and performance cars with tightly packed engine bays tend to take longer.
What causes wiring harness failure?
Common causes include heat damage, moisture, corrosion, rodent damage, poor repairs, and normal wear over time.
Can a bad wiring harness cause the check engine light?
Yes. Damaged wires can send faulty signals to sensors, triggering the check engine light.
How do I know if my wiring harness needs replacement or just repair?
If damage is isolated to a few wires, repairs may be possible. But widespread corrosion, melted insulation, or multiple breaks usually mean full replacement is the better option.