How to Rewire Your 20 Year Old Minivan

Introduction

If you're like me, you love your trusty old minivan. It's been with you through thick and thin for 20 years, but the wiring is starting to go. Lights flicker, the radio cuts out, and you've got some wonky electrical gremlins popping up. Don't despair! With some basic tools and my step-by-step guide, you can rewire your 20 year old minivan and get it back in good working order.

Rewiring a vehicle may seem intimidating, but it's very doable for a DIYer. In this article, I'll walk you through everything you need to know to rewire your aging minivan from start to finish. From assessing the existing wiring to splicing new wires, I'll cover all the key steps. We'll also look at troubleshooting electrical problems, safety tips, and tools needed for the job. Let's get started!

Gather Tools and Materials

Before we dive in, we need to gather the right tools and materials. Here's what you'll need:

• Wire stripper - for removing insulation from wires
• Crimping tool - for attaching connectors
• Electrical tape - for insulating connections
• Cable ties - for securing wires
• Multimeter - for testing circuits
• Wiring diagram - find one specific to your minivan's make/model/year
• Replacement wiring harness - match to your vehicle
• Heat shrink tubing - for protecting splices
• Needle-nose pliers - for reaching tight spots
• Work lights - for visibility

You'll also need new copper core automotive wiring in various gauges, connectors, fuses, relays, and terminals. Make sure to get the right components for your particular minivan. Safety gear like insulated gloves and safety glasses is also a must.

Inspect and Assess the Existing Wiring

Before replacing any wiring, you need to thoroughly inspect the existing system. Here's how:

• Check under the dash - this is where wiring harnesses converge, look for damage
• Inspect the engine bay - examine wires near hoses, belts, and hot components
• Follow each wire run - look for pinched, damaged, or corroded wires
• Wiggle wires and connectors - check for intermittent breaks or shorts
• Use a multimeter - test voltage drops and continuity

Pay close attention to the insulation. Cracked, brittle, or melted insulation can expose wires and create shorts.

Also sniff for burning smells which can indicate damaged wiring. Make notes on any problem areas to be repaired.

Disconnect the Battery

Before doing any wiring work, always disconnect the negative terminal of the battery. This cuts power to the whole system and prevents getting shocked.

Use an adjustable wrench to loosen the battery cable terminal clamp. Remove the cable entirely and tuck it away from the terminal.

With the battery disconnected, you can now safely work on the minivan's wiring without risk of shocks. Just don't engage the ignition or press the start button.

Remove Interior Panels

To access wiring harnesses, you'll need to remove some interior trim panels. This includes:

• Dashboard cover
• Kick panels by the floorboards
• Door panels
• Center console if equipped

Panels are usually held on with screws and plastic fasteners. Use a trim removal tool to pop the fasteners loose carefully.

Set all panels, screws, and fasteners aside organized so you can easily reinstall later. Be careful not to crack any brittle plastic pieces.

Remove the Main Wiring Harness

Now you can access the wiring harness running under the dash. This bundles all the wires connecting to lights, gauges, switches, and electronics.

To remove it:

• Unbolt it from the steel frame
• Unplug connectors to all devices
• Cut cable ties securing it in place
• Coax it out carefully without damaging wires

Lay the harness out on a clean surface and inspect for damage. Repair or mark any bad wires.

Install the New Wiring Harness

Replacing the old wiring harness with a brand new one is the most thorough option. Here are the steps:

• Obtain a compatible harness for your specific minivan
• Starting at one end, reconnect devices like you removed the old harness
• Route the new harness just like the original
• Secure with fresh cable ties, leaving room for movement
• Double check all connectors are fully latched

Take your time and refer to the wiring diagram as needed. Getting everything hooked up correctly now prevents issues down the road.

Splice and Solder New Wires

If you only need to repair a few wires, targeted splices are an option. Here's how to splice:

• Cut back damage on both wire ends, leaving 1-2" clean copper
• Strip about 1/2" insulation off both ends
• Slide heat shrink tubing over one wire end, out of the way
• Twist the clean copper ends together tightly
• Solder for the strongest connection
• Slide heat shrink over the splice and heat to seal

Repeat for any other spots needing new wire. Take it slow and make each splice carefully.

Label Wires and Connectors

For your own sanity later, take time to label wires and connectors. Use a printed diagram and permanent marker to identify:

• Wire colors and functions - for example "Red - Front left turn signal"
• Connector pinouts - label wires going into complex connectors
• Fuse boxes - mark which fuse powers each component

This helps immensely with troubleshooting down the road.

Test All Circuits

With the harness installed, test every electrical component.

• Turn the headlights, wipers, and accessories on
• Start the engine and check gauges
• Use a multimeter to check for voltage at devices
• Wiggle wires while testing for potential shorts

Finding and fixing issues now is much easier than later.

Reinstall Interior Panels

Once everything is electrically sound, put the interior back together by:

• Carefully fitting the new harness back into place
• Snapping panels back on with fasteners
• Replacing all screws to secure tightly
• Reconnecting the battery cable

Keep an eye out for sharp edges that could rub through insulation over time. Apply protective wraps as needed.

Troubleshooting Electrical Problems

Even with a perfect installation, electrical gremlins can eventually crop up. Here are some tips for troubleshooting down the road:

• Use wiring diagrams - identify the problem circuit
• Check fuses - replace any blown fuses
• Inspect connections - loose connectors can cause cut-outs
• Look for chafing - wires rubbing on metal edges
• Wiggle test wires - intermittent shorts are hard to find
• Consider replacing old components - switches, relays, motors go bad over time

Take a methodical approach to isolate the issue.

Conclusion

Rewiring an aging minivan is very achievable for a DIYer armed with some basic knowledge. The key is taking it slow, using quality components, properly splicing wires, and thoroughly testing all systems.

While it takes some work upfront, a freshly rewired minivan will be much more reliable and problem-free for years to come. Your ol' reliable van has a lot of life left with a new wiring harness!

I hope this guide gives you the confidence to tackle this project and get your beloved minivan back in tip-top shape. Let me know if you have any other questions!