I wanted to do a DIY version of the ultimate camping mod but realized once I opened up the back door trim that the wiring had changed at some point.
Here's that thread if you're interested in what I discovered.
I paid for the 2 day access to Toyota Information System (TIS) and spent nearly every waking hour of those two days downloading every technical document for my 2020 TRDP. In the 500 MB of PDFs I found the updated wiring diagram. Once I had the proper pinout, I was ready to go.
Without further ado, here's how you install your own
interior door release and window buttons for 2019 and newer 4runners.
Disclaimer: I am not liable if you break anything. Do this at your own risk. I highly recommend you be comfortable with basic wiring and splicing techniques before proceeding. If not, I recommend you seek out the guy that makes plug and play harness kits that accomplish the same thing.
Estimated time: One full day, possibly two. Be safe and plan to spend a whole weekend on this.
Tools I used: - 10mm socket and wrench or driver
- Panel pry tool(s)
- Wire cutters
- Wire strippers
- Needle nose pliers
- Standard pliers
- Drill with step bit
- Heat gun
- Lots of lighting
Supplies and parts (linked when available):
Step 1: Remove the back panel of the hatch. Remove the small trim piece at the base of the strap handle. After that, use your 10mm socket and remove the strap. I recommend you pry out the two lights. Unplug them and set them aside. Then take your pry tools and pop the big trim panel off. Once it feels like all of the retainers have popped off the door, lift the whole trim piece up towards the top of the door. The "window ledge" of the big black trim piece slots into the bottom of the window sill. Lifting/sliding it up towards the top prevents bending or breaking the trim piece.
Step 2: Pick your button locations and drill away to match just the size you need for the button to slide in. Many people pick the top of the black piece on the "window sill" of the hatch so you don't have to route wires. The issue is that depending on the situation, people may see those buttons from outside and could easily enter your vehicle with a coat hanger.
I chose to put my buttons on the driver's side D pillar. This panel is super easy to pull out and has lots of space behind it for wire (I keep my excess back drive cam cable here). Just know that if you do it like I did, you're adding a lot of extra time to the job, but I feel that it is definitely worth it for what I'm trying to accomplish. You do you and go with what you'd like.
Step 3a (buttons not on door): Route your wires. Take 5 different colors of wire (or one color with lots of tape markers and continuity checks along the way) and route them from the ECU inside the back door (the black box between the speakers that has two white harnesses) to your switch location.
For me this meant running wire through the grommet in the top of the body, into the rubber conduit, into the door, down the side of the door staying in the channels to the left of the window track, and into the working area in the door near the ECU.
As you can see, I taped all of my wires together along with a sharp tipped wire coat hanger. The hanger worked as a trocar, punching its way through the rubber membrane since there isn't enough space along the factory wiring bundle to run 5 more wires.
WARNING: Be careful if you do it this way since the sharp end of your coat hanger could slash through factory wire insulation. Go slow and methodically.
I forgot to take pictures of it, but once you're past the window and in the actual working area of the door, the factory wiring bundle is routed through a rubber piece within the speaker mount. Next to the factory wires is an unused hole for another wiring bundle. You do need to punch it out, but this way you can keep the wires cleanly routed towards the ECU.
Once I routed the wire I then ran flexible, semi-rigid 1/4 inch wire conduit over the wires through the door segment and other areas between the rubber grommets where the wires could be susceptible to abrasion or wear through.
Step 3b (buttons on door): Drill your holes wherever you decide and then run 5 different colors of wire (or one color with lots of tape markers and continuity checks along the way) from the ECU inside the back door to your switch location. I recommend using some sort of wire loom/conduit and tape or zip tie the conduit/loom to secure areas that won't get in the way of any mechanism or trim retainers.
Step 4: We'll start with wiring for the door release. Find harness W10. It is the 1st (or top) harness plugged into the black box which is the ECU.
Find the wires coming out of pins 7 (light green) and 24 (gray). These are unchanged from older 5th gen models so if you've gotten this far and have a 4Runner that's older than 2019, this will work for you. Here's what it looks on the wiring diagram:
And these are the pins. Remember, the diagram below is if you're looking at the female side of the harness. The wires you want are at the back of the respective front pinout. Again, you're looking for 7 and 24.
Step 5: You've got two options on how to join the wires. You can use those minimally invasive taps listed in the supplies list. The problem I had was that they were too minimally invasive. They never penetrated the factory wire insulation and I wasted too much time troubleshooting the problem. Maybe you'll have better luck.
Or you can do what I did and spliced the wires together. I used a heat shrink wrapped crimp joiner. I wasn't happy with the results, but it worked.
Step 6: Now test your connection. Take the ends of your wires at the switch end and touch them together. If you hear the hatch mechanism activate, you're all set. Go ahead and wire the switch up.
Polarity doesn't matter so just hook it up as you see fit. I just crimped some female spade wire terminals and then shrink wrapped each wire terminal at the switch.
Step 7: We'll follow the same general principles for the window switch.
This time you're going to be looking for the wires coming out of pins 1, 13, and 14. Luckily we're still using the same harness, W10.
- Pin 1: green wire and is your common/ground/
- Pin 13: black wire and is window down
- Pin 14: red wire and is window up
Here's the wiring diagram for it:
And another reminder of the harness pins.
Step 8: Time to once again splice (or tap) into these wires with your 3 remaining new wires. I got frustrated with these cheap amazon taps and instead used the heat shrink crimp joiners like before with my new wires twisted into one side of the joiner and the remaining harness wire on the other.
Step 9: Test your work before wiring the switch.
WARNING: Do NOT test the window with the hatch open. This switch bypasses the safety feature that prevents the window from opening and closing when the back door is open. I found out why that safety is in place. If you roll the window up or down with your back door open, gravity lets the window scrape along the back of the speakers and you will have two new lovely scratches in your tinting and may potentially cut your defroster wires.
Before you permanently secure the wiring to the switch, take your new common wire (the one that was green off pin 1) and touch it to the bare end of one of your two new wires. If you hear the window motor actuator kick in, you know that your common and that one other wire is correct. Now just touch the other wire to your common and if that works, it is safe for you to wire them to your switch and button it all up.
Step 10: Wire your window switch. The common wire should more than likely go on the middle terminal of your switch. Then wire the other two up and just make sure your switch is installed in the correct orientation so you're not pushing the button down to roll the window up (unless that's your style). I ran out of spade connectors so instead just stripped plenty of wire, looped them through the holes in the switch terminals, twisted each switch terminal wire tight, and then shrink wrapped all the terminals. You can see in the picture I used some braided loom on the window switch to protect the excess wire I had left over.
Then just screw your switches in tightly and in the correct position. Lastly put the trim panel, handle strap, and door lights back on in the reverse order you used to take them off.
Step 11: Look at your handiwork and enjoy a beer while doing so.
I hope this helped someone along the way. Thanks for stopping by.
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