How to Wire Switches and Accessories on Your Toyota Tacoma

Adding accessories to your Toyota Tacoma is essential when transforming your truck into a modified Tacoma Beast. For many, though, the prospect of wiring accessories and switches is intimidating. Cutting and splicing wires is a daunting task and dealing with electricity comes with inherent risks. These deterrents are only accentuated by the high cost of many switch systems on the market.

If you want to wire switches and accessories on your Toyota Tacoma without cutting factory wires or breaking the bank, you have come to the right place. With the right products, some time, and a little know-how, you can have your accessories seamlessly powered in no time. The fitment is so precise that these switches will even look like they came from the factory.

With several options, including left of the steering wheels harness, below the head unit, and overhead, you have the flexibility to customize your Tacoma in the perfect way for your preferences. You can even use a combination of the above if you have multiple accessories or require more switches.

Read on for a detailed guide to easily wiring your Toyota Tacoma. By the end, you will know exactly how to install the right plug-and-play system for your needs, flawlessly integrating your accessories into an easy-to-use hub.

1.     Before we jump into the installation of the left of steering wheel wiring harness for the        Toyota Tacoma, it is important to note that it plugs into the cargo light harness. If your truck does not have the cargo light option, fear not—the connector is still hiding behind the trim panel to the left of the steering wheel.
2.     With a panel pry tool, pry outward from the top of the panel.
3.     When loose, the panel will easily fall out. Disconnect the auto high beam harness and cargo light harness (if equipped).
4.     With the panel free, locate the cargo light connector. Plug it into the new harness (you should hear a click).
5.     If you have the cargo light switch, the larger connector will plug back into it to retain factory functionality. If you do not have this switch, skip to the next step.
6.     Install your switch(es) into the switch panel.
7.     Plug the two-pin harness together, then plug the green connector directly into the switch.
8.     Install spade connectors on the two exposed wires.
9.     Measure and prep your wire that will go to the fuse box and relay, respectively. We prefer 20-gauge wire for relays and 12v sources. Color matching the wires is a good idea—green to the fuse box and red to the relay.
10.     Install spade mating connectors in the same fashion as the spade connectors. Plug the corresponding wires together.
11.     Feed the wires through the back of the panel. You should be able to pull them out near the gas pedal.
12.     Connect your 12v source wire (green) to your fuse tap using the same spade connector method. This will allow you to provide a minuscule amount of power to your switch.
13.     Determine whether you want your accessory to be functional at all times (including when the truck is turned off) or only when the vehicle is turned to the accessory mode or fully on.
14.     Run your green wire with the fuse tap to the fuse box. Remove the fuse you have chosen, add it to the bottom slot of the add-a-fuse fuse tap, insert a very small fuse to the top slot (in line with the wire), and plug the fuse tap back into the original fuse location.
15.     Guide your red wire through the firewall. You will need to use a tool to assist in this process. Wire hangers are a great option, but any small diameter, semi-flexible rod will work. You can secure the wire to your tool using electrical tape to make the process as easy as possible.
16.     Using your rod, poke a hole in the boot behind the brake pedal. Pull the rod through and into the engine bay. The wire will follow.
17.     Cut the wire to the proper length, leaving a bit of slack. Install a female spade connector to the end of the wire and connect it to pin 86 on your relay.

1.     Remove the head unit by pulling on the shroud surrounding the unit. Then, remove the four 10mm bolts surrounding the head unit and pull the unit straight out.
2.     Take a picture of the connectors on the back of the head unit. This will make reinstalling the connectors in the right locations easier when putting the unit back in place. Unplug the connectors by depressing the tab and pulling on the plastic portion of the connector, not the wires.
3.     Reach into the opening and behind the ridge containing the HVAC controls. Locate the ECT button, depress both the top and bottom tabs, and push the button out. You can do this simultaneously or by pinching the top tab first, then the bottom, removing the button in a rocking motion.
4.     Once the button is out of the panel, remove the connector and take the button off. Do not let go of the connector, as it can be challenging to retrieve.
5.     Plug the below-unit harness into the ECT button connector.
6.     Feed the two-pin connector into the panel in the direction of your new switch. Reach your hand back behind the panel and push the two-pint connector through the switch hole. Connect the switch harness to this connector to keep it accessible.
7.     Reinstall the ECT button with the new harness.
8.     Attach red and green wire lengths to the corresponding leads using the spade connector method.
9.     Feed the wires through the hole where your new switch will be mounted. Grab them from the back by reaching behind the panel. Find the best path you can to route your wires from this location to beneath the steering wheel.
10.     Route the wires to their appropriate destinations—the fuse box and through the firewall to the relay.
11.     Reinstall your head unit and shroud.

1.     Remove the overhead console by pulling it down. The clips holding it will release.
2.     Disconnect the single harness connected to the console.
3.     Plug the male end of the new harness into the factory harness.
4.     Route your fuse tap and relay wires through the headliner and behind the A-pillar trim. To do this, run the wires along the headliner, remove the A-pillar trim, and route the wires down toward the kick panel.
5.     To remove the A-pillar panel, use a pick, credit card, or something similar to wedge beneath the circular piece near the top. Pop it out and remove the 10mm bolt beneath it. Be sure that the negative terminal is removed from your battery, as there is an airbag behind the trim panel. Starting at the top, pull the panel away from the side and then pull upward.
6.     Fish the wire through the gap in the A-pillar. You can use a tool, like a wire hangar, to accomplish this by fishing upward from the kick panel, securing the wire to your tool, and pulling it back down.
7.     Once the wires are routed, zip tie the wires behind the looming to ensure they do not obstruct the airbag.
8.     Attach the wired you just ran to the wires included in the overhead harness. Install your switch into the panel, connect the harness, and reinstall the overhead console, tucking the wires out of the way as you do so.
9.     Run the wires identically to the other harness installations, ultimately arriving at the fuse box and through the firewall to the relay.
10.     Reinstall the A-pillar trim piece.

1.     Reconnect the negative battery terminal.
2.     Start the truck, turn the light stalk to either parking mode or low beams, and ensure all the switches light up.
3.     Make sure your new switches are dimmable and in sync with the factory switches.
4.     Put everything back together as it should be—you are good to go!