How To Crimp And Solder Wires

Date 3rd Feb 2025

Creating secure and reliable electrical connections is a crucial skill for anyone working with auto-electronics or wiring. Whether you’re dealing with your vehicle’s lighting, communication, refrigeration, power management or otherwise, understanding how to crimp wires and how to solder wires is essential. This guide will walk you through each method, ensuring your connections are safe, durable, and professional-grade.

If you’re more of a visual learner, we’ve also included our helpful Klarmann YouTube tutorial from Ryan below:

How to Solder Wires

Strip the Insulation

Start by stripping the insulation from the wire you’ll be soldering onto. Use side cutters to make a small cut – just enough to slice through the insulation without cutting the wire underneath. Then, push with your fingers to separate the insulation. Repeat this process for the second wire you’re connecting.

Prepare the Wires

Once the insulation is removed, twist the exposed copper strands tightly together. Ensure the strands are smooth and compact – nothing should be sticking out. This prevents sharp points from piercing the heat shrink later.

Heat the Soldering Iron

Turn on your soldering iron (we’re using a Milwaukee model with an indicator light that signals when it’s ready).

Tin the Tip

Once the iron is hot, tin the tip by applying a small amount of solder to it (this helps transfer heat more effectively).

Solder the Wires

Place the soldering iron under the twisted copper strands. Feed solder from above, letting it melt and flow evenly into the joint. The finished joint should look shiny and smooth, with no sharp edges or strands poking out.

Apply Heat Shrink

Cut a piece of heat shrink tubing long enough to cover both wires and the soldered joint. Slide it over the connection and use a heat gun to shrink it. The tubing will seal the joint, and you’ll see glue oozing out slightly at the ends, indicating a watertight seal.

That’s it for soldering! Now, let’s move on to crimping.

How to Crimp Wires

Crimping an Anderson Plug

Prepare the Wires

Use the pins as a guide to measure how much insulation to strip from the cables. Carefully strip just enough insulation to expose the copper without cutting into it.

Crimp the Pins

Place the stripped wire into the pin, ensuring all copper strands are inside. Use your crimping tool to secure the pin. Check the connection by tugging gently – it should not come loose. Repeat this process with the other wire.

Insert into the Anderson Plug

Match the wires to the plug’s polarity (positive and negative). Push the pins into their respective slots until you hear a click. Tug gently to confirm the connection is secure.

Crimping a Deutsch Plug

Prepare the Wires

Measure the required insulation length using the pin. Strip the insulation carefully, ensuring no copper strands are cut. If the strands flare out, twist them neatly before inserting into the pin.

Crimp the Pins

Slide the pin onto the wire and use Deutsch crimpers to secure it. The crimp should leave a visible indent on the pin. Test by pulling gently to ensure it’s firmly attached.

Insert into the Deutsch Plug

Identify pin numbers on the plug (e.g., pin 1 and pin 2). Generally, black wires go into pin 2, and red wires go into pin 1. Push each pin into the plug until you hear a click, then test the connection by pulling gently.

Add the Wedge

Insert the wedge into the plug. Align it carefully, avoiding the tabs, and push it down until it sits flat.

Ready to get started?

As you can see mastering how to crimp wires and how to solder wires is a valuable skill that can save time and ensure the longevity of your electrical connections. Whether you’re creating watertight joints with soldering or assembling secure plugs with crimping, the techniques outlined in this guide will help you achieve professional results every time. And if you’d rather leave it to a qualified and experienced auto-electrician, our friendly team at Klarmann Automotive Solutions is more than happy to help – simply contact us and we’ll see what we can do for you.