Dome Light for Constant Dash Cam

Hello there. I'm looking for the cleanest possible install without running cables down my pillars, all to add a dash cam to my 2020 Tacoma SR5. I have an auto dimming mirror with compass, but no Homelink. That means I don't have constant power, so the Dongar adapter won't help me there. I'm not great with electronics, but I was able to test the plug going into my rearview mirror and see one wire lights up in ON/ACC only. The dome light is the next easiest place to access, so has anyone actually tapped into the dome light for constant power? Is there a device to piggyback into those pins? I've tapped into blade pins for an aftermarket power socket (12v lighter), but these pins look a little more complicated.

 

You should have constant power, it's just not something the standard mirror uses. I unplugged my stock mirror and plugged in the factory homelink and it has constant power and I changed 0 wiring. That is not a feature I like personally, but mine lives in a garage so it's not a big deal. If it lived outside, I would mod it to only be on when the vehicle is on.

IIRC there are some wiring harnesses that piggyback off the factory plug that let you run a dash cam or radar or whatever, but haven't looked into the specifics of how they're wired and if they use the constant or switched power source. Might have to repin the Dongar if that is what it's supposed to do to pull power off the hot lead.

 

I'm wondering if this solution will work. I pulled the overhead console off and think I may be able to run a wire from whatever constant power is available in this plug (or the one on the far right, just out of the photo, which connects to the main inside the truck) to the plug for my rearview mirror. Then I'd be able to use the Dongar adapter that works with Homelink-enabled trucks. It looks to be 20 gauge wire and I'd have to figure out how to piggyback the male leads, but does this seem feasible?

 

No, I don't have constant power. I have power to the upper right pin when the key is in the ON position only. The Dongar team emailed me about this problem and mentioned 2020 is a mixed year for the SR5, where some dealers ran the power all the way to mirror plug (mandatory to run the Homelink mirror), and some didn't run it because auto dimming mirrors only need to work when the truck is driving.

Here's the light-up from the key being ON. No other pins light up in any key position.

 

Haha, agreed! You would think Big Yota would leave the constant power there for everyone to upgrade if they wanted, but not anymore. I guess the cost to run that wire was more than they expected to make in aftermarket sales.