How much juice is coming out of the rearview mirror harness?

I think I had a couple misconceptions when I purchased the USB adapter for the rearview mirror harness:
1. That it would be constant power, even what the truck is off. Nope.
2. That it would supply enough power to charge a GoPro, or keep a GoPro running. Nope.

So did I buy a piece of junk adapter? Or is the mirror just not getting enough power? I expected 12v of constant power, seems like that's not the case. I've tried a dozen or so USB cords to rule that out. I've tried the same cords on a ciggie lighter adapter, and they all work fine.

 

Check the pins

 

The mirror is switched 12v - you can tell how it turns off when parked. It should put out enough amps to power a GoPro, I have a two-camera front and rear dash cam and a altimeter display powered by it.

I don’t have a GoPro, but isn’t it powered by USB? If so, are you using a 12v -5v USB adapter also?

Best to run a dedicated power line from the fuse box up the A column if you want Non-switched power, and don’t try tapping the dome light unswitched power supply leads in the overhead console, you will mess up your DRLs…

 

The cigarette lighter plug works fine because it is hard wired to the battery or a fuse. That's why you can get a hot connection even when the truck is powered off. The rear view mirror doesn't need power after the truck is off, so the engineers at Toyota didn't hard wire it to the battery.

I have my Garmin Mini connected to my rear view with the USB dongle adapter and it only powers it on while the truck is running. If I want to run it in "parking" mode then I need to run a cable directly to a fuse.

 

you talkin about this one?

$37 Dongar Dash Cam Power Adapter (12-pin Type A) - Compatible w Toyota Tacoma (15-23), select Highlander, Tundra, Sienna; Honda Ridgeline & more. USB Power, Connects to Rearview Mirror. Easy Install!

https://www.amazon.com/gp/product/B07DMW3DML?ie=UTF8

its 10w, what does your gopro pull?

 

The mirror has a battery connection and a switched connection. It just depends on which wire is used in the harness op bought.

 

My mirror does not have a full-time battery connection (2017).

 

The 2017 does have 2 sources of power, and I added an attachment in my post providing that info. If it doesn't apply to certain years, it would be annotated, like in the attachment in this post. Still shows that the 2017 has both sources of power.

 

Yes it does have both switched and unswitched 12v. The unswitched powers the garage door opener part of the mirror, even when ignition is off.
https://www.tacomaworld.com/threads...dash-cam-install.650486/page-12#post-22964317

 

That's the exact one I have installed in my truck. The internet says my GoPro (hero5 black) will accept UP TO 5v/2a, so this thing should do it.

Also, my garage door opener works when the truck is off, so it's always getting power. But this adapter has never worked when the truck is off, and despite it's claim that it should deliver the gopro's max input voltage, it doesn't work. It basically trickle-charges the camera, and stops charging at all if the GoPro is recording.

 

The SimpleUSB uses the switched power from the rear view mirror. Otherwise it would drain your battery. Also, I don't believe the adaptor will provide 2 amp output.

 

If you really want to kill your battery and risk damage to your truck, you could modify the SimpleUSB. Snip the switched positive wire from the buck convertor (shown red here) and tie it into unswitched positive wire (shown blue here). Do this at your own risk.

 

I just don't know how people are powering USB devices with this thing at all. It's a piece of garbage in my experience. I'd be fine with it only working on acc. that's how the rest of the truck is, as annoying as that may be.

My '03 limited explorer had way more options than my '17 limited Tacoma, including maintaining acc until you open the doors for things like window switches and the stereo, auto-dimming sideviews, always-on cig lighter ports, auto-locking doors when you exit, power seats, and more. But that thing was good for a $500 repair every 500 miles. Tradeoffs I guess.

 

I've had a Simple USB in my Tacoma for 2-1/2 years, and one in my wife's Armada for 2 years. Both power Garmin 56 dashcams, and both work perfectly. Your GoPro probably draws more power than the adaptor can provide.