How to Replace the Turn Signal Wiring on a 1987 Toyota Corolla

Introduction

Replacing the turn signal wiring on your 1987 Toyota Corolla can be a straightforward project that will restore proper function to your turn signals. While it may seem intimidating, it only requires some basic tools, a repair manual for reference, and a little bit of time and patience.

I recently replaced the turn signal wiring on my own 1987 Corolla, and learned firsthand everything involved in the process. In this guide, I'll walk through all the steps I took to replace the wiring and get my turn signals working properly again.

Gather the Necessary Tools and Supplies

Before getting started, you'll want to make sure you have everything you need for the job. Here are the basic tools and supplies I used when replacing my Corolla's turn signal wiring:

• Electrical tape - for wrapping and insulating wire connections
• Needle nose pliers - for grasping and stripping wires
• Wire crimp connectors - for securing wire connections
• Wire stripper - for stripping insulation off wire ends
• Voltmeter/multimeter - for testing circuits
• Repair manual - contains wiring diagrams and specifics for your model year
• Replacement turn signal wiring - buy pre-cut to the correct lengths

Having these tools and supplies on hand will make the wiring replacement much easier. The repair manual is especially helpful for identifying the correct wire colors and circuits.

Locate and Access the Turn Signal Wiring

The first step is to locate the turn signal wiring under the dashboard and gain access to it.

• For my 1987 Corolla, I first had to remove the lower dash cover panel by removing a few screws and clips. This exposed the wiring underneath.

• The turn signal wires on most Corollas of this vintage run from the steering column along the inner firewall and back behind the fuse box.

• Use your repair manual to verify exactly where the turn signal wiring runs in your year model. This is important to prevent accidental damage.

• You may need to remove or detach other wires and hoses that block access to the turn signal wires. Taking photos along the way helps note where everything was originally located.

Gaining easy access to the entire turn signal wiring run is crucial for the next steps.

Remove the Old Wiring

With access to the wiring obtained, you can now detach and remove the old turn signal wires:

• Start by unplugging the wire connector at the steering column coming from the turn signal switch.

• Then locate where the wires feed into the fuse box and disconnect them.

• Clip any plastic wire ties bundling the turn signal wires to other wires. This allows you to completely remove the old wiring.

• One section at a time, grasp the turn signal wires at both ends and gently pull them out of the run along the firewall. Note which color wire was in each location.

• Remove any old wire fasteners or clips from the firewall if they won't be reused.

Thoroughly removing the old damaged wiring prepares for installation of the new replacement wiring.

Install the New Turn Signal Wiring

Installation of the new turn signal wires involves carefully routing them into position:

• Begin by feeding one end of the new wires into the opening behind the fuse box.

• Continue routing the wires along the run toward the steering column hole. Keep them bundled together and align them with any existing clips.

• Take care not to over-bend or kink the new wires. Too tight of a bend can damage the wiring internally.

• Use the repair manual wiring diagram to connect the correct color wires to the right positions at the fuse box and steering column connectors.

• Attach the steering column plug to the turn signal switch.

• Use wire ties, clips and fasteners to neatly route and secure the new wiring along the firewall.

• Double check that wiring positions match the repair manual diagrams before reattaching dash panels.

Proper installation of the new turn signal wires ensures many more years of reliable operation.

Testing and Finish Reassembly

Once the new turn signal wiring is fully installed, test operation before reassembling:

• Turn the ignition key on and activate the left and right turn signals. Check that the dash indicators function properly.

• Use a voltmeter to test for 12V power at the turn signal fuse positions when activated.

• Verify the hazard flashers cause both turn signal lights to blink as they should.

If the turn signals operate normally, you can go ahead and reinstall the lower dash panel and any other interior trim pieces that were removed. Your 87 Corolla once again has fully functioning turn signals!

Replacing old brittle wiring seems difficult, but carefully following the steps I've outlined makes the job very manageable. Take your time, use the correct tools, and refer to the manual whenever in doubt. Your patience will be rewarded with many more years of reliable service from your vintage Toyota.