High Level Dashcam install (formerly No Switched Interior Fuses for Dashcam Installs)

2023 CX-50 PPT
I wanted to carry over my Blackvue 900X Plus dashcam from my CX-5. The X and X Plus series require 3 wire connection (ground, battery and switched). The switched is required to put the cam into "Parking Mode" when the ignition is turned off and where these cams themselves actively monitor battery level and shut off if voltage drops too low.

After testing, I realized that the CX-50 is like the current CX-30 and I think also Mazda3 vehicles where there are no actual switched fuses in the interior box.

There are a couple of solutions CX-30 owners have used but none appeal to me that much--running the switched power cam wire to the engine fuse box or tapping into the front USB ports (I'm assuming like the CX-30's our USBs shut off after 5-6 minutes post-ignition off). Some have also used OBD2 power-only adapters that have a switch for always on/accessory which shuts off after X time, but that would be a rather messy install with some wiring going neatly to the interior fuse box and then the OBD connector for the switched wire.

I'm going to think about this further and see what the best solution for me might be, but I don't want to wait too long as where I live is notorious for bad drivers and a lot of hit and run scenarios.

EDTI: I also now see some M3 owners have tapped into a harness in the A pillar which has all 3 types of wiring required, but will need to check the CX-50 wiring diagrams to see if it has something similar. Some of the Mazda OEM Dimming and Homelink mirrors when installed as an accessory also tap into that same pillar connector or into existing sensor wires behind the base mirror. That seems to me like the best solution if possible.
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On my CX-30 I ran it into the engine fuse panel. Wasn't that difficult to do and it looks all very neat and tidy.
Thank you--do you remember which exact fuse you used there, and did you use a fuse tap or another method? Also, did you add a wiring loom around the switched power wire for heat protection on the engine side?

I remember seeing someone who had done that on one of the CX-30 forums (maybe it was you) and went through a firewall grommet and said it wasn't terribly difficult.
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The rear view mirrors wth homelink usually have constant 12v, switched 12v and ground. Almost all of them.
Shutdown the car, lock if you want, wait few minites inside and try the homelink button. If it works the you got the 3 comnections in your mirror.
The rear view mirrors wth homelink usually have constant 12v, switched 12v and ground. Almost all of them.
Shutdown the car, lock if you want, wait few minites inside and try the homelink button. If it works the you got the 3 comnections in your mirror.

I'm going to tap into the same wiring the instructions for the CX-50 auto-dimming Homelink mirror harness use. Two harnesses are used, one for the mirror and a second from the upper console (lights/sunglasses area). Started yesterday but ran into some minor obstacles and ran out of time. Easy peasy to run the rear cam wire after doing it in my two previous CX-5s, but took me a while to figure out exactly how to remove the top 3rd piece on new mirror sensor cover design (instructions in the mirror install sheet are unclear). Carefully pulling back/cutting away the wiring harness foam tape took forever. Also realized the wire taps I got are way too big physically even if they are the same design as those Mazda provides with the mirror (the parallel wire push down snap over type), so will instead use smaller form T-taps.

I know they are not always reliable and can loosen over time, but I wish someone made a 3 wire mirror tap for dash cams that require both switched and always active power connections like my Blackvue X series. The mirror installation sheet shows the associated slots on the mirror harness itself, so I could just tap into that one connector and not have to futz with the upper sensor and console removal and second wiring harness.
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First of all, apologies for not taking pictures. I'm one of those dive right in and get 'er done types, plus I work in my garage and lighting is terrible for photos since I use one of those LED headlamps for focused task lighting.

While the Mazda accessory auto-dimming Homelink mirror part # is the same for both the CX-30 and 50, I found what seems to be a wiring discrepancy at least for my PPT which already has that mirror from the factory.

On pg 5 of the attached Mazda instructions, they seem to suggest that the sky-blue wire in the 8 pin harness connected to the front of the overhead lights/sunglasses holder console is ignition switched, and on pg 6, the green wire from the 5 pin connector that's from the 3rd top piece sensor cover (C) is battery/constant, or at least that's my interpretation. However, after using the T style wire taps, my dashcam would power up but not go into parking mode when the vehicle was switched off--it would instantly shut down. So, I then used a test probe and determined that at least for my CX-50 trim, those wires are indeed powered but in the opposite manner. The sky blue wire is constant and the green wire is switched. Once I redid those connections, the dashcam is working completely as expected.

Otherwise, the applicable instructions are sound except for those regarding how to remove the 3rd sensor cover part (C). Mazda helpfully obscures the detail on that piece where you have to release tabs. ;). You want to look at the large cutout in the part of the cover closest to the windshield and about 3/4's of the way up each side. It is not the open rectangular hole below that. In the correct opening, you will see a flat piece of slightly textured/hatched plastic. The instructions say to press that to release, but I was only able to do so by lifting the tab with my fingernail from the end closer to the dashboard (lower end). That then releases it and permits that cover to be slid down and off as indicated.

For my dashcam (Blackvue DR900 X Plus 2CH), the hardwiring harness has built in fuses so not too worried about electrical problems and the circuit used appears to be 15 amps (10-15 is recommended for dashcams when tapping into existing ones). I had to cut the 3 harness wires and splice them together and shrinkwrap, because it was way too long for this short distance run. There is very limited open space under the sensor covers unlike in my 2019 CX-5. There is also a component that runs very hot, so I wanted to avoid the wires touching that squarish metal sensor. I ended up having to wrap the extra length of both the power and the rear cam wires around the base of the mirror outside of the sensor cover. It was a bit of a challenge to get the wires out of the way of the snap-together cover parts and through only the small opening for the mirror base.

FYI if you reattach the battery to test things mid-stream as I did, don't be scared if you see an airbag system issue alert come up on the center gauge. That will occur if the harness that attaches to the 3rd C sensor cover piece is still disconnected at that stage (among other things, it controls the passenger airbag light alert in that cover piece). You can just then erase the associated DTC(s) in the standard manner for current Mazda vehicles via the Connect system buttons and diagnostic mode (very easy to do).

Later edit: I also learned that when the battery is disconnected, you have to re-initialize iStop if you have it on your vehicle.

If anyone has any questions, happy to help where I can.


  • VA40V7210_Auto Dimming Mirror_INST_EN_Rev_B.pdf
    1.4 MB · Views: 418
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