Auto-Dimming Dash Light Mod 5th Gen 4Runner – How To Dim The Lights in Your 4Runner

Auto-Dimming Dash Lighting for 5th Gen 4Runner

Auto-Dimming Dash Lighting for 5th Gen 4Runner – Compatible with 2014-2019 5th Gen 4Runner, Not Compatible with 2020+

Sometimes a mod isn’t a way to improve stock capabilities, it’s a way to bring your vehicle up to what should be stock. In this case, that’s unlocking your 4Runner’s ability to do something it’s already built and programmed to do. Certain 5th Gen 4Runners are pre-wired for auto-dimming lighting. Specifically dimming the dash and infotainment touch screen when in a dark environment, or turning the brightness up when you’re in a sunny one. In the case of TRD Pro or Limited models, that’s a feature that’s active as soon as you take delivery of your vehicle.

But for the rest of us, we have to switch between Off or Daytime Running Lights for bright environments and On for dark ones. Not a big deal, but easy enough to fix if you’re willing to roll the dice with international sellers on Amazon or eBay.

Find It Online 

  • Auto Light Control Sensor (Toyota part#89121-50020): Check Price

Note that when I ordered my sensor, it shipped from China using China Post. If you don’t have any experience with China Post that means it took a long time, approximately six weeks, from purchase to delivery.

You can of course buy the part directly from Toyota. But doing so will cost you $200 compared to the $10-$15 you can spend if you’re willing to take the gamble on sketchy Chinese sellers on Amazon or eBay. But more on that in a minute.

Tools & Materials

It doesn’t get much easier than this.

  • Interior Trim Tool
  • Something to clean your windshield afterward (optional)

Check to Make Sure You’re Compatible

A fair bit of research has lead me to believe that the only models pre-wired for this sensor are the SR5 Premium, the TRD Off-Road Premium, TRD Pro, and Limited. In other words, it is models with the upgraded infotainment system, and the Pro and Limited models already have the sensor installed from the factory so they won’t benefit from this mod. So if you have either variety of Premium models, read on.

But if you don’t, it’s easy enough to check by popping off the dash plug and taking a look. Simply slip your trim tool under the blank plug at the center of your dash, and pop it out. If there’s a wire connected to the plug, you’re in the game. If not, better luck next time.

Step 1. Remove Blank Plug

remove bank plug

Just like step zero, all you’ve got to do is slip your trim tool in between the blank plug and your dash and use the power of leverage to pop it up. If your 4Runner is pre-wired, the connector will be attached to the plug.

Step 2. Swap on the Sensor & Install

Installing Auto Light Control Sensor

Carefully, so you don’t drop the wire back behind the dash, disconnect the wiring and attach it to your sensor.

Feed the wires into the hole, and pop the Sensor back into the hole. Note: This part of the process appears to be irreversible, so do not “test fit” the sensor before attaching it to the wiring harness.

Testing

That should be it. So start your 4Runner turn on your headlights, and test the sensor by either adding light (with the flashlight on your phone) or blocking it (covering the sensor with your hand). When the sensor detects light, it should brighten both your infotainment screen and your dashboard illumination to the same levels you have when in Daytime Running Lights or Off. When the sensor doesn’t detect light, it will dim both to the settings you previously had for On.

Final Thoughts

The functionality of the sensor is exactly what it’s supposed to be. It’s especially useful if you like your interior extra-dark at night, but still want to have more visible instruments when your headlights are on during heavy rain or snow. Not exactly a game-changing mod, but it’s nice to not have to switch between headlight settings while driving in variable weather. It’s a feature that came stock on my wife’s fifteen-year-old Corolla, but Toyota makes you DIY for a much newer 4Runner. Weird.

So I’m left wondering why I had to do it in the first place. Not that I actually needed to, obviously. But why is Toyota not doing it at the factory? My 4Runner had everything it needed to run this sensor. Toyota even wired a dummy plug so it’s not like they saved the cost of installation. Their $200 parts price is obviously inflated, even if the back-door price on Amazon and eBay is artificially cheap. But in the cost of a $40,000 truck, it seems bizarre that Toyota isn’t willing to throw in the sensor.

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Mtnbiker40
Mtnbiker40
8 days ago

Just installed on my 2018 ORP, works fine on the dash lights. I was hoping it would work on the clock too, but no. I drive with the lights on during the day and have a hard time seeing the clock with sunglasses on. It would be nice if it brightened the clock during the daytime also.

timos22
timos22
9 days ago

Now if there was also a way to get the auto on headlights – that would be really nice!

Will 42
Will 42
17 days ago

I added it to my 2018 TRD Off Road a year or so ago. Makes no sense why the sensor wasn’t included in the first place.

Patrick Parachoniak
Patrick Parachoniak
21 days ago

My 2014 SR5 Premium Canadian version does not have the wiring unfortunately.

Behren
Behren
22 days ago

This worked on my SR5 Base, fyi. Thanks for the article!

Jeff Steffens
drifter
Jeff Steffens (@steffensj2gmail-com)
22 days ago
Reply to  Behren

really? My 18′ SR5 Premium it has the wires at the plug but not into the dash. So it doesnt work on mine. I read on the forums you have to connect those wires behind the radio on the SR5’s for this to work.

Behren
Behren
22 days ago
Reply to  Jeff Steffens

Oh man, I just checked for the wires at the plug, as the article stated, so I thought I was good.

Jeff Steffens
Jeff Steffens
18 days ago
Reply to  Behren

ya, I don’t think so. One guy I saw on the forum had to get a ~$50 wire harness and then take out the radio to get it to plug in for the whole thing to work.

Behren
Behren
18 days ago
Reply to  Jeff Steffens

Thanks for the heads up!

Jeremy Chambers
Nomad
Jeremy Chambers (@jeremy-chambers)
23 days ago

I just recently picked this exact item up and about to install it this weekend. I seen this and heard that about 2 years ago it was only a $3 to $5 part. Crazy to think that for Toyota it would have probably been less than $1 and they didn’t just install it to begin with lol.

Keith
Keith
23 days ago

I absolutely hate that Toyota cheaped out on this piece for the 4Runner. And it’s worse because in the 2022, it’s a different pin for it so I have yet to find it for less than $80. I’m jealous you Pre-2020 guys can find it for under $10

timos22
timos22
9 days ago
Reply to  Keith

What is the part # for 2020+? I did not read the title and got the part mentioned here – but it is a 6 pin sensor and the wire on my 2020 has a 4 pin connector…

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