How to repair and solder automotive wiring harnesses.

Plus helpful wiring harness solder repair videos to help guide you. 

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What is soldering?

Soldering is a common technique to join two pieces of metal together by melting and flowing a filler metal (solder) into the joint. It is often used in electronics to make permanent connections between components and in various other fields, such as plumbing and jewelry making. In this case, however, we're referring to automotive wiring harnesses.

One important thing to note: 
Wire quality is paramount. To demonstrate its importance, scroll down and check out our bad and good wire-quality videos. When you're performing a solder repair with low-quality wires, the moment an open flame contacts that wire, it immediately begins to disintegrate. 

How to solder wire harness wiring

Step-by-step guide on how to sodler wires

DIY Wire Repair

Step 1: Gather materials

  1. Gather your materials: You will need a soldering iron, solder, wire stripper, wire, and a helping hand (optional).

Specific Tools

1. Solder iron/heat gun or heating torch

2. Wire cutter or crimp tool

3. Solder (quality is important)

4. Electrical tape (super 33+)

5. Heat shrink (we prefer the type that has the glue already built-in)

6. Split loom

Strip the insulation

Strip the insulation off the wires: Use a wire stripper to remove about 1/2 inch of insulation from the ends of the wires you want to join. Be sure to remove any stray strands of wire that may have been cut.

Tin the wires

Tin the wires: Tinning the wires means applying a small amount of solder to the exposed wire. This helps to make a better connection when the wires are soldered together. To tin the wires, heat up the soldering iron and touch the tip to the exposed wire. Then, touch the solder to the wire, letting it flow onto the wire.

Helping Hand

Place the wires in the helping hand: If you are using a helping hand, clamp the wires in place so they are easy to work with.

Adding heat

Heat the wires: Touch the soldering iron to the wires, making sure to heat them evenly.

Solder application

Apply the solder: Once the wires are heated, touch the solder to the joint between the wires. The solder will melt and flow into the joint, forming a strong connection.

Remove iron

Remove the iron: Once the solder has flowed into the joint, remove the iron and allow the connection to cool.

Testing

Test the connection: Once the connection has cooled, gently tug on the wires to make sure they are securely soldered together.

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Summary

Soldering can take some practice, but with a little patience and attention to detail, you can create strong, permanent connections between wires. Just be sure to use caution when working with the soldering iron, as it can get very hot and cause burns.

For a more, in-depth how-to on how to perform a correct solder repair, check out this post; Connector Repair: Wire Solder Technique.

Top-Selling Solder, Wire Harness, and Pigtail Repair Tools

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Eric Palazzolo

Eric Palazzolo is founder and president of FindPigtails.com, a Houston-based company dedicated to providing high-quality automotive connectors and top-shelf customer service to its clients in the collision repair industry.
Eric-Palazzolo-001-300w

Eric Palazzolo is a founder and president of FindPigtails.com, a Houston-based company dedicated to providing high-quality automotive connectors and top-shelf customer service to its clients in the collision repair industry. He also founded metricsmule.com, a website, marketing, and automotive SEO company with a blog on marketing and SEO.