Ultimate Sensors & Wiring Harness Buying Guide
Your car is a complex network far beyond the accelerator and brake pedal. There's a complex network of wiring and sensors that constantly communicate with each other and send information to the vehicle's Electronic Control Unit (ECU). When you take your car to a mechanic for a warning light on your dashboard, they'll plug a diagnostic tool into the ECU and download the messages that should tell them what sensor is having an issue.
Wiring harnesses connect the signals together to transmit the power.
How your car runs depends on these sensors and the messages they transmit. Some sensor issues won't prevent your car from moving, but there are some that stop your car from starting or functioning as it should.
To help our customers understand sensors and wiring harnesses, how they work, and how to select the correct replacements online, we've created this comprehensive guide.
We’ll cover:
- What are sensors and wiring harnesses?
- What are the most essential sensors on your car?
- Why do they matter?
- How to tell if a sensor needs changing
- The types of sensors and wiring harnesses available online
- The sensor and wire harness brands and options
- How to choose the sensors and wire harnesses
- Frequently asked questions about shock absorber parts
What Are Sensors and Wiring Harnesses?
Your car can have anywhere between 70 and 100 sensors. For example, there are between 15 and 30 sensors in the engine alone. The actual number depends on the make and model of your motor.
They're a complex of highly intelligent and sensitive sensors and electronic devices that constantly monitor conditions internal and external to your car. They're reading temperature, speed, tire pressure, fuel and fluid levels, and so much more.
They then convert that data into signals for the ECU to process. The ECU can then optimize performance and safety, and can also adjust various functions. So, if you're driving along and your check tire pressure light comes on on your dashboard, it's because a sensor within the wheel alerted the ECU that the tire pressure was below safe levels.
The wiring harness is the bundled system of electrical cables, connectors, protective sheaths, and wires that connects these sensors and other components to transmit the power and signals. They're like the nervous system of your car, connecting everything from the battery to the lights, engine control units, and fuel pump—literally everything.
Without the wiring harness, there wouldn't be the energy and information flow that primary car functions need.
And now, with modern cars, it's even more complicated than an ABS or actuator sensor. Autonomous driving and advanced driver assistance systems are creating modern cars with more complex sensors and wiring harness setups than ever.
What Are The Most Important Sensors on Your Car?
Some would say all the sensors are important, but some are essential to making your car ignite and the wheels move.
ABS sensor
Each wheel hub has an ABS sensor. They're a relatively inexpensive part that prevents wheel lock-up under hard braking and helps to maintain your car's stability and control overall.
It's a misconception that an ABS sensor is only for hard braking. But as you brake with more aggression, the sensor sends a message to the ECU to regulate the brake pressure, allowing you and the car to keep traction and you to keep control of the car and avoid skidding.
Oxygen sensor
Oxygen sensors are located in the exhaust unit. They're one of the most active sensors, detecting oxygen levels in the exhaust up to seven times per second. It's an essential component in helping your car maintain the optimal air-to-fuel ratio needed for efficient engine performance. They also help reduce emissions.
As soon as you engage the ignition and the engine is running, the oxygen sensor sends rapid signals to the ECU so it can adjust the fuel delivery and stop the engine from running too rich or lean. Rich means too much fuel, and lean means too little. Without it, you'll notice poor fuel economy, increased pollution, and decreased engine power.
Mass air flow (MAF) sensor
The MAF sensor is one of the sensors that your car wouldn't function without. On some models, you can start a car with a faulty MAF sensor, but it won't really function and will likely shut off the ignition, so much so that you can barely drive it a few kilometers.
The MAF sensor sits in the engine's air intake system between the air filter and the throttle body. It measures the volume of air entering the engine and sends a signal to the ECU for it to calculate and deliver the precise amount of fuel needed for combustion. It also makes the ECU regulate the air-fuel ratio.
Without a functioning MAF, your car will likely not start. And if it does, you'll experience issues like rough idling, poor acceleration, and even engine damage.
Crankshaft Position Sensors
Crankshaft position sensors sit near the engine's flywheel or ring gear. The crankshaft itself is an essential car component that regulates the internal combustion engine by converting the up-down motion of the pistons into the rotational power that turns the wheels.
The crankshaft position sensor monitors the rotation and position and then sends the information to the ECU so it can precisely time fuel injection and ignition.
Like the MAF sensor, it's unlikely that your car will run at all with a broken crankshaft position sensor. If it is malfunctioning, your engine will likely stall, misfire, or be almost impossible to start. And if it does start, it will likely stall again soon after.
We won't go through every sensor in the car, but these are some of the most essential that get your car going and keep it moving. The wiring harness simply routes all the electrical circuits that contain these sensors to create a stable current flow for safety and performance. They're highly resistant to heat and moisture and generally make the entire electrical system neat and manageable.
Why Do They Matter?
The sensors matter because they're constantly feeding your car's ECU with the information it needs to keep your car moving and functioning efficiently. Yes, you can argue that some of them are not as essential, but that depends on your take on it. For example, the tire pressure sensor sending a pressure warning to the ECU that brings a warning light to your dashboard might not stop your car from moving. And if you get out and see that your tire isn't flat, you might ignore it for as long as you can.
And, yes, it might just be a sensor issue that needs replacing. But it's more likely to be a genuine tire pressure warning that could mean your wheel will either deflate and cause damage to the wheel hub assembly, rotor disc, or blow out at speed and cause a serious safety issue.
Or, there are the sensors we've talked about that simply won't let your car start or will make it run poorly if they're malfunctioning.
And for the wiring harness bundle, the sensors are nothing without a way of communicating with each other and the ECU. The wiring harness bundle creates a protected path for the constant transmission of power and messages that keep your car running.
How to Tell if a Sensor Needs Changing
Sensors are good because they will usually tell you if something is wrong. That said, your dashboard doesn't display all errors and information. If there's an issue with your engine, the check engine light will come on, and the same for your fuel or tire pressure. Remember that your car will have at least 70 sensors, and not all of them have a corresponding dashboard display message.
But your ECU will know. If your car isn't running as it should or a dashboard warning light appears and you're not sure why, a diagnostic test using a professional onboard diagnostic scanner is relatively inexpensive from a mechanic.
Some of the common signs that you might need a sensor change include:
- Dashboard warning light
- Poor engine performance
- Reduced fuel efficiency
- Unusual engine sounds
You shouldn't need to change the wiring harnesses that often. Some of the areas of your car are more prone to wearing down the wiring harness, such as the bundle surrounding the ABS sensor. With correct care, wiring harnesses can last the life of a vehicle. Signs of failure include:
- Exposed or frayed wires
- Intermittent electrical problems
- Melting
- Burning insulation
The Types of Sensors and Wiring Harnesses Available Online
There are so many sensors on your car that we can't mention them all in detail. Looking more broadly, here are the types of sensor and wiring harnesses online:
- Engine sensors and wiring harness bundle
- Position sensors and wiring harness bundle
- Pressure sensors and wiring harness bundle
- Temperature sensors and wiring harness bundle
- Speed sensors and wiring harness bundle
- Driver assistance sensors and wiring harness bundle
- Safety sensors and wiring harness bundle
The Sensor and Wiring Harness Brands and Options
At Parts Avenue, we work with the best sensor and wiring harness bundle brands to give our customers the most premium, affordable original equipment-level parts.
If you need to buy sensors and wiring bundle kits, we stock numerous ABS wheel speed sensors and wiring bundles to suit multiple makes and models of cars.
Mpulse
Mpulse is an excellent provider of vehicle sensor replacement parts engineered to match original specifications. For original equipment-level parts, they deliver precision-engineered parts for durability and unmatched accuracy.
They also manufacture ABS sensors and wiring bundles suitable for a long list of car makes and models, so you're likely to find suitable sensors and wiring harnesses online at Parts Avenue.
How To Choose The Right Sensors and Wiring Harness
Run a diagnostic check.
It's unlikely that you will know what the issue is by the warning light on your dashboard. We would recommend first running a diagnostic check using a professional onboard diagnostic scanner for accurate sensor issue information.
The ECU will display codes and error messages that tell professionals what sensor is causing the issue. And if it doesn't directly link to a sensor, mechanics can usually use their professional judgment to find the actual sensor causing the error.
Find the correct sensor.
Once you know which sensor is malfunctioning, you can look for the correct sensor and wiring harness bundle online. Some of the best sensors and wiring bundles will come as a kit. They're affordable, but not necessarily easy to replace unless you know what you're doing. We would advise that, unless you're trained, you let a mechanic change the sensor and fit the wiring bundle for you.
Frequently Asked Questions About Shock Absorber Parts
How can I tell which specific sensor or wiring harness is causing an issue?
Sometimes, it's easy to understand which sensor is causing an issue. For example, if your tire pressure light is always on despite the tires being at the correct PSI, it's likely a faulty sensor. Always run a diagnostic test using professional equipment so the ECU can tell you the issue.
You can find an issue with the wiring harness on inspection.
Are aftermarket sensor brands reliable compared to original equipment manufacturer (OEM) options?
Yes, aftermarket brands are just as reliable as original equipment manufacturer parts. They're specifically designed to match or better the specifications of OEM parts, but at a more affordable price.
How often should wiring harnesses and essential sensors like ABS or oxygen sensors be inspected or replaced?
You don't necessarily need to check ABS or oxygen sensors unless you're seeing warning lights on your dashboard. Sometimes, with a full service, mechanics will check these for you. They have an extremely good lifespan and aren't as susceptible to wear and tear as other car parts.
You can find the sensors or wiring harness bundles online at Parts Avenue. We stock a range of original-equipment-level sensors and wiring harness bundles at the most affordable price on the market.
Start your search today with Parts Avenue, the most-trusted car parts provider in Canada.