Auto wiring harness repair: As an integral part of the vehicle, wiring must always remain in working conditions.
However, as cars undergo a lot, the auto wiring harness gets exposed to high temperature, ice, water, and salt conditions and tends to get damaged with time.
When the wire is damaged, the only solution is to repair or replace it, and everyone tries to fix the harness first for obvious reasons.
It’s for the same reason auto wiring harness repair has become a core competence in the auto industry.
Table of Contents
- Causes of auto wiring harness failures:
- Warning signs of Auto wiring harness failures:
- Repairing/replacing auto wiring harnesses:
- Things to consider of auto wire harness repairs:
- Know the circuit and choose the right connection way.
- Heat shrinks tubing to secure wires:
- Replace the damaged wires with the new ones:
- Ensure connectors and back shells are in good condition:
Causes of auto wiring harness failures:
- Bend in the harness: Sometimes, due to high mileage, bumpy roads, and adverse weather conditions, the harness wires wear down or grow stiff over time.
- Exposed wires: Heat, rain, cold, or extreme vibrations break small pieces in the harness, exposing wires. These exposed wires may lead to many faulty conditions.
- Harness malfunctioning: Some procedure errors during manufacturing, like wrong wire size, incorrect crimping, or improper assembly layout, lead to harness malfunctioning after installation.
Pigtail wiring harness
Warning signs of Auto wiring harness failures:
- Your vehicle’s lights will not operate properly as they get power from the car’s battery.
- Flickering the vehicle’s lights also indicates wiring issues in your car.
- Wiring issues may also lead to a dead battery, creating problems while starting the vehicle.
- If you are experiencing sudden stall or rev along with jerking, lurching, or stuttering, the reason is probably bad wiring.
- Wiring malfunction also leads to the illumination of the engine light.
Automotive wire chewed
Repairing/replacing auto wiring harnesses:
A typical auto wiring harness comprises the following components:
- Shrink tubing
- braid/string tie for holding wires
For any wiring malfunction, it is less probable that you will replace the entire harness. When your auto wiring harness fails, find out the reason and then replace only the damaged or affected parts in the harness.
However, it does not mean that a single harness will last a lifetime after being installed in the vehicle.
You may need to replace the entire harness if the damage is extensive, like melted wires. Also, for sensitive systems like airbags, it is always good to replace the harness completely if any error occurs.
The cost of buying a new wiring harness depends on the size and location of the same.
Sometimes, the damage is so much distributed that replacing it is less expensive than repairing the harness.
So, whether you need to replace or repair the harness depends entirely on the damage size, budget and location of the harness.
Auto wiring harness components
Things to consider of auto wire harness repairs:
The process of auto-wiring harness repair is more complex due to the sensitivity and complexity of the harness.
The small diameter of wires and terminals, restricted space, and networked electronics make it challenging.
Here, we are mentioning a few points that can ease your work to some extent.
Safety always comes first, so disconnect the battery to cut off the power supply when repairing wires. This will keep you and the entire circuit safe from sudden short circuits.
Know the circuit and choose the right connection way.
Nowadays, vehicles carry complex computer-controlled electrical systems, which carry specific components in their construction. You need to know the circuit before starting to repair it. Some circuits have very low voltage signals; too much solder or long splice may lead to signal error due to resistance.
If you need crimp connectors during repairs, get the right size, as too big and too small will cause errors. Also, strip off the required insulation when you install a crimp connector so you do not crimp the wire’s coat.
Heat shrinks tubing to secure wires:
Black electrical tape is common in vehicle wiring, but don’t use it to protect the repaired part. With high moisture and temperature, it may become loose or may unwrap. Use it only to bundle wires.
Use heat shrink tubing to protect wires from dirt, moisture, and other contaminants, making the solder or crimps more reliable.
Sometimes, professionals use lighters to heat the tube, but we advise you to use a heat gun. Heat gun helps you give the right amount of heat without melting wires and nearby circuits.
When repairing multiple wires, it is good to use heat shrink tubing on individual wires and then use a large tube to bundle all the individual wires together for a neat and reliable result.
Replace the damaged wires with the new ones:
If the damage on the wire is extensive, you are supposed to replace it with a new one.
Break wires carefully out of the harness:
Always be careful while removing a damaged wire from the harness so you do not damage near connectors and wires.
Choose Automotive grade wiring:
Automotive grade wires, a strand type wiring, differ from normal wires as they can handle vehicle vibrations and heat.
Use the correct gauge wires.
Too thin wire may fail during high power surges, while too thick can add extra resistance to the circuit.
While repairing, ensure you use the same spec wire installed earlier.
You must know that switches, signals, and circuits use different-sized wires; for example, headlights use thin gauge wire while the battery uses a wire with thick gauge.
Don’t forget the voltage drop along with the wire length. So, to combat the voltage drop, you must pick large gauge wires.
Here is a chart that details the wire gauge breakdown concerning amperes and length.
|Total wire length in feet|
|AMPERES||10 Amp – 120W||16ga||16ga||16ga||14ga||14ga||14ga||12ga||12ga||10ga||10ga||10ga||8ga||8ga||4ga|
|15 Amp – 180W||16ga||16ga||14ga||14ga||14ga||12ga||10ga||10ga||8ga||8ga||8ga||4ga||4ga||4ga|
|20 Amp- 240W||16ga||14ga||14ga||12ga||12ga||10ga||10ga||8ga||8ga||8ga||4ga||4ga||4ga||4ga|
|25 Amp – 300W||14ga||14ga||12ga||10ga||10ga||10ga||8ga||8ga||4ga||4ga||4ga||4ga||4ga||1/0ga|
|30 Amp – 360 W||14ga||14ga||12ga||10ga||10ga||8ga||8ga||8ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga|
|40 Amp-480 W||14ga||12ga||10ga||8ga||8ga||8ga||4ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga|
|50 Amp – 600 W||12ga||12ga||10ga||8ga||4ga||4ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga|
|60 Amp – 720 W||12ga||10ga||8ga||8ga||4ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga|
|70 Amp – 840 W||12ga||10ga||8ga||4ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga|
|80 Amp – 960 W||12ga||8ga||8ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga|
|90 Amp – 1080W||12ga||8ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga|
|100 Amp – 1200 W||10ga||8ga||4ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga||N/A|
|120 Amp- 1440 W||10ga||8ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga||N/A||N/A|
|140 Amp – 1680 W||10ga||4ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga||3/0ga||N/A||N/A|
|160 Amp – 1920 W||8ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga||3/0ga||N/A||N/A||N/A|
|180 Amp – 2160 W||8ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga||N/A||N/A||N/A||N/A|
|200 Amp – 2400 W||8ga||4ga||4ga||1/0ga||1/0ga||1/0ga||1/0ga||3/0ga||3/0ga||3/0ga||N/A||N/A||N/A||N/A|
Choose wire colors:
Wire harnesses come with a particular color combination, and keeping the same color coordination during repair will make your future repair convenient.
Terminate the wire to the connector properly.
Ensure connectors and back shells are in good condition:
Check and repair connectors, hoods, and back shells when repairing damaged wires. If these parts remain damaged, repairing wires won’t do anything good.
Automobile harness wire repair
Indeed, you cannot know everything about wire repairs, as there are customized harnesses with specific components and circuits.
If, even after several attempts, you fail to repair your auto wiring harness, contact Cloom. We are an expert in all sorts of wiring harnesses and cable assemblies.