So after following an old post (on mdxers.org) on mirror tapping a RD, I found a few new things.
First when you pry open the left side compartment of the rear view mirror housing, I found a white connector with two relevant wires- black (ground) and green (at least on the 2017 MDX). The mirror tap post had mentioned a red (power) and black (ground). Anyway I assumed that the green was power and used a Blendmount MTX series tap to put the black tap in the black and red wire tap in the green.

Voila, the RD gets power when I start the car and shuts down on turning the engine off. I did not have access to a voltmeter so could not measure the Volts.
Am I plugging in the correct housing? Apparently so, but not sure why the post said a red wire instead of what I have - green wire to tap into.

Comments from who have done this before???

 

Good thing you posted this thread, I wanted to hardwire my dashcam but uncertain if I should use the fuse tap or the mirror to get power. Do you have any photo to share what it looks like? Also, if anyone would like to post what fuse number you used to get the power from?

 

I used the green and black wire connections in the white connector. You will see a white connector when you open the left side of the mirror housing. No splicing or adding fuses is needed, as the MTX Blendmount series has a built in fuse in the wire taps.
Don’t have pics but you don’t need any, when you open the left side of the mirror housing you will see the white connector. I should have also used a Voltmeter for measuring the voltage but just forged ahead without it.

 

Off topic but I think it's easier to tap into the fuse for power. You can still achieve a clean look and easily fix/revert without having to remove any panels.

 

My experience was the opposite - a mirror tap takes 5 mins when you have the right tools and achieves a cleaner look. The left panel already has a notch in it to insert a flat-head screwdriver and comes apart easily. Blendmount MTX mirror tap wire rocks!!

 

In order to tap into the fuse for power, you'll need to take apart the A-pillar cover to hide the power wire.

 

Ahh sorry I should have clarify. I meant for dashcam. Reason being I haven't found the same needle tap similar to Blendmount for dashcam. I've done both dashcam and radar installation and I agree, the taps for the radar is easier going in the mirror. But due to the lack of taps for dashcam I found it easier to go to the fuse box. I'm not at all comfortable splicing wires in the mirror.

No need, you can tuck the wires all the way down. The rubber/pillar is pretty flexible.

 

Just finished installing the Street Guardian SG dashcam, you can tuck the wires between the rubber seal pretty easy. I ended using the cigarette power cord instead of hardwiring it to the fuse box, do you know what fuse number to use for the fuse tap connector.

 

Fuse #13 ACC