This certainly looks like my fuse box in the floor of my E400d cabriolet boot but where did you attach the negative black wire please?
A friendly local garage confirmed that the blue fuse bottom right in my picture is a switched fuse. So I ran my Nextbase hardwire kit from just left of my rear view mirror, then behind the plastic cover for the SOS stuff, along the top of the windscreen and down the right windscreen pillar, then a pretty hard and sharp turn back towards the steering wheel and then down the door reveal. I then gently prised off the door sill plastic cover and ran the cable under that (there's also enough space to hide the little box of electrics that I think monitors the car battery state had you used a non-switched fuse - also not recommended by my local garage).
They commented that the margins on the battery are so low on this car that by the time this circuit cuts the power to the camera the car battery wouldn't have enough juice to start the car!) I'll never know since I'm using a switched fuse.
Then run the cable up and along the left side of the seat and exit under the rear hinge for the seat and under the carpet/cardboard into the boot space where the fuse box is. Use the blue fuse I mentioned and if you pull the floor up a bit more from around the fuse box lid you'll see a steel cage with some handy threaded bits welded to that cage. this serves as the connection for the black earth cable (you'll need to find some nuts of your own for this threaded bar).
All works a treat!
My next step is to install the rear view camera. But I need to purchase a telescopic phone holder that will stick to the rear parcel shelf and convertible roof cover as the camera needs to be fairly high up to effectively capture those drivers that now think the covid 2 meter rule applies to following the car in front!!!!
This cable will run down the path of the electrical loom providing the power to the rear brake light to somewhere near the hinge for the nearside rear seat, then down and under the nearside plastic sill cover, up the door reveal near the passenger footwell fuse box (confirmed by my friendly local garage to only contain non-switched fuses), forward along the bottom of the nearside window pillar and then finally up the nearside window pillar and windscreen and across the top of the windscreen to the camera.
They commented that the margins on the battery are so low on this car that by the time this circuit cuts the power to the camera the car battery wouldn't have enough juice to start the car!) I'll never know since I'm using a switched fuse.
Then run the cable up and along the left side of the seat and exit under the rear hinge for the seat and under the carpet/cardboard into the boot space where the fuse box is. Use the blue fuse I mentioned and if you pull the floor up a bit more from around the fuse box lid you'll see a steel cage with some handy threaded bits welded to that cage. this serves as the connection for the black earth cable (you'll need to find some nuts of your own for this threaded bar).
All works a treat!
My next step is to install the rear view camera. But I need to purchase a telescopic phone holder that will stick to the rear parcel shelf and convertible roof cover as the camera needs to be fairly high up to effectively capture those drivers that now think the covid 2 meter rule applies to following the car in front!!!!
This cable will run down the path of the electrical loom providing the power to the rear brake light to somewhere near the hinge for the nearside rear seat, then down and under the nearside plastic sill cover, up the door reveal near the passenger footwell fuse box (confirmed by my friendly local garage to only contain non-switched fuses), forward along the bottom of the nearside window pillar and then finally up the nearside window pillar and windscreen and across the top of the windscreen to the camera.
