[RedBaron]

If you are looking to add a radar detector or dashcam and are looking for a source of switched (Acc) and/or constant (B+) power, you can obtain these from the mirror or sunroof area.

I used the sunroof area as my dashcam had a power adapter and the sunroof area has lots of space to stash it (the mirror area does not). So, if your car has the sunroof, both switched (Acc) and constant (B+) power and ground is available at the glass motor connector above the roof cabin light/switch panel. The panel comes down quite easily... just open the glasses holder and undo the two screws there, then unclip the front of the panel pulling down, and slide forward to free the hooks at the back. Then undo the three connectors from the panel.

This pic shows the opening once the panel is removed:

This pic shows the connector and which wires to use. I needed to use all three for my dashcam w/parking mode, but you may only need Acc and Ground:

This is what I did - rather than splice into the wires in the harness, I soldered some metal posts onto the ends of my wires, and then just pushed them into the back of the connector to make friction contact with the pins in the connector, then taped the bundle to keep them in place. I hope the connections will be firm - they have been so far (~3 months) - but if they start getting intermittent, I'll splice them properly:

 

[RedBaron]

If your car has the autodim rearview mirror, but no sunroof, you can instead use the connector/harness inside the mirror mount 'box'...

The plastic casing around the mirror mount is split in two parts (sides) and held in place by clips between the two sides. You need to carefully pry between the sides and pull them apart to the left and right - warning, you can mar the plastic with your pry tool!. Alternatively, get a pair ot rubber gloves (for the friction) put both hand's fingertips on one side, press against it and jerk it away from the other side.

This pic shows the right side handheld in place, but the left side removed, to give you an idea:

Then the connections are shown in these photos from different angles. NOTE: I did NOT use these, and the markings are based on Mazda's wiring diagrams. If you want to use these, it'll be a good idea to test with a multimeter first!

 

[CX-50 Meridian Edition]

Very nice how to, and great pics. Thanks for sharing!

 

[Blockisle9]

Excellent!
Thank you

If your car has the autodim rearview mirror, but no sunroof, you can instead use the connector/harness inside the mirror mount 'box'...

The plastic casing around the mirror mount is split in two parts (sides) and held in place by clips between the two sides. You need to carefully pry between the sides and pull them apart to the left and right. This pic shows the right side handheld in place, but the left side removed, to give you an idea:
View attachment 1071
Then the connections are shown in these photos from different angles. NOTE: I did NOT use these, and the markings are based on Mazda's wiring diagrams. If you want to use these, it'll be a good idea to test with a multimeter first!
View attachment 1072
View attachment 1073

 

[CTt3CX50]

Another nice little write up you have provided. For those with the autodim rearview mirror, I wonder if this cable would work on the CX-50? There are a few different variations available for just about any dash cam install. I know it will work on the Miata (obviously and I am awaiting warmer weather to install my dash cam with the Thinkware specific cable) but his description says it is compatible with Mazda USA cars with a ten pin connector. For anyone who may want to try it vs. splicing, they can reach out to Sergey. He is very helpful and quick to respond. If it should work, it is nice that you can hide the entire cable within the mirror mount box! The connector on the Miata is plugged into the back of the mirror so I will need to figure out a way to try and hide it upon install.

MX5Things PnP Dash Cam Cable